When deciding to go to the Galapagos Islands, my gut instinct as a lifelong-confirmed backpacker was then "how can I do this cheaply?"
I say "on the cheap (relatively speaking)" as there's no way around the fixed fare of 420 USD to get a return flight from Quito or Guyaquil, not to mention the $100 dollar National Park entrance fee.. and they even toss in an extra $10 for some tax or other. That's US$530 right there before you've even left the ground!
It's what comes on TOP of this that I'm going to consider the "cheap" bit that I set out to accomplish 
Normally people assume you need to organise a cruise to have any decent chance of seeing the Galapagos, and these can range anything from $650 to $$$$$$ depending on how many days you want to go for and what type of ship you want.
"Nay!"..I say! I've found that it's entirely possible to arrive at the main town on Santa Cruz island, Peurto Ayero, and organise your own mini day-trip excursions to nearby islands, and even scuba dives, while spending around $50/day including accommodation and all food!
The airport beside Santa Cruz is on a small nearby island in the north side called Baltera, and from here you must get a 50 cent ferry across, then a $3 bus down south to the town. Once in town, it's very easy to set yourself up with a $20 private hotel room with A/C and TV, and even Wifi! Even out here in the middle of the Pacific ocean you remain connected to your Facebook Wall posts! (or GlobeNotes obviously!)
The volcanic island of Isabella is about 2 hours by boat from Santa Cruz, and boats leave daily for only $25-30. Bear in mind that boats only leave Santa Cruz at 2pm, and then leave Isabella only at 6am, so an overnight is required.
Many people have told me that, with these two islands (Isabella alone being 52% of the total Galapagos landmass) you can actually see MOST of the wildlife that you see on the far off islands that require cruises, the main exception being red-footed boobies and a few other bird species which are only found on the remote islands. Giant-Tortoise, Sea lions, Penguins, and TONS of Iguana. You name it.. you can see them all within about 15 min boat ride from the coast of either Isabella or Santa Cruz. Score!
On my first day in Santa Cruz I had the "typical" local Ecuadorian set-meal for $3 for lunch. In these kinds of restaurants there's no menu, and you basically are told that either fish, chicken or mystery-meat is to be served with rice, beans and usually a potato-soup. You also get free juice, including one called "Tamarindo" that was delicious, tasting somewhat like Ice-Tea. It's a great way to get fed cheaply.
I then wandered down the 2.5km paved trail to Turtle Bay as I heard there was some sort of beach there and I fancied a bit of a swim in the Pacific (yes FINALLY I'd reached the Pacific Ocean!) ... little did I realise that Turtle Bay, with it's talc-like soft white sand, perfect body-surfing waves, and miles of pristine coastline was pure paradise! HERE, I had found the single BEST beach I've been at on this entire trip.. and quite possibly for about 5 years! I laid my clothes down beside some Iguana tracks and dove right in... the utter bliss of the perfectly room-temperature water carressing my aching body was enough to almost make me comatose! So.. eh.. yeah.. check that beach out pronto... thankfully it's part of a nature reserve too so it won't be destroyed.
Did I mention Iguana tracks? Yep, that'll be the black marine Iguanas! When I first saw them back on Turtle Bay I was mesmerised. It really surprised me that I'd feel so close to a lizard, but the little guy's cute expressions and tameness (most animals on the Galapagos are insanely tame... even birds!) just captured my heart and I'd even consider getting one when I get home! ... that was the first day when I saw 2 ... since then, I've probably seen about 2,000! They're everywhere! Many times at first you don't see them as they've evolved the black colour so they can blend in with the Galapagos' lava rocks... but when they start sprawling themselves in front of your path at every juncture, lazing in the sun, oblivious to the fact that you almost squished their lizard-brains underfoot, they kinda become part of the background! Still cute little buggers though, I think I used up an entire memory card photographing them, trying to get that "perfect" shot.
So what else have I done "on the cheap"?
Well on the second day I took a $25 snorkle tour (including snorkle equipment and even a walking tour of an island!) off Santa Cruz and swam with juvenile sealions, and marine iguana! My cheapness even extended to my choice of underwater disposable camera, but when my $7 "Braun" underwater camera stopped working just as a baby seal came within 1 foot of my chops, looking at it's reflection in my goggles, I swore I'd never again skrimp on camera equipment. CHEAP GERMAN BASTARDS! Kodak all the way from now on.
After the snorkle I headed off to Isabella at 2pm. The trip over is a good 2 hours on the $30 boat, and the waves were choppy as hell. A German guy got sick on board, but I got chatting to a sound American guy from Colorado called Lee. He'd just returned from an 8 day cruise and was able to tell me a lot about the evolution of the animals in the Galapagos as he had read Darwin's book, but also because he had a very good guide on the boat. (Admittedly this is one downside of going solo, you don't have a guide to inform you every step of the way)
Got a nice hotel in Isabella with cable TV, AC and a lush ORTHOPAEDIC bed for $20 a night called "Sandrita". Highly recommend room #2.
The third day was a tour of Isabella. Isabella is nowhere NEAR as developed as Puerto Ayora on Santa Cruz island, so you're somewhat limited in the kind of tours you can take once you arrive. Myself and Lee got chatting with one of the boat guys at the harbour and agreed on a snorkling trip out to some nearby islands called "Las Tintorellas" for only $15 each! Bargain again!
It was indeed a bargain as the tour included sightings of equatorial Penguins (they are related to the Antarctic penguin, and would have arrived after making it up the west South American coast using the cold Humbolt Current. Thank Lee for that bit of info!), plus an island packed SOLID with Iguana. I mean, every foot of the island had a black Iguana either digging a nest or spitting at you out of fear. We had planned to snorkle with the penguin, and at one point we did manage to swim with one, but unfortunately due to rainy weather which started today, visibility was pretty crap. Still though, for $15 for 4 hours I'm not complaining!
Unless you're really interested in so-so volcanoes, though, Isabella doesn't really have much else going for it when you're going solo. The west of the Island is supposed to be fantastic for wildlife due to the cold currents, but that would require a 2 day cruise at least. So we had a quick visit to the Tortoise Breeding Centre to see some of the HUGE giants and called it a day. Despite the brief time I had at the breeding center, I found the Giant-Turtles one of the most fascinating creatures on the Galapagos. To look into the faces of the older ones is to stare at 150 years of experience! The things those older ones must have seen. They almost carry an air of intense wisdom in their expressions.
At one time hunted almost to extinction by whalers and pirates for their meat and oil, the population of various species are gradually gaining strength. But it's not fool-proof and the recent global warming and onslaught of El Nino has wrecked havoc on the animals here.