There are a couple of relatively cheap (under or around $100 used) interfaces that I've tried and used, but only one I'd suggest. Here's a novel of a post.
1) If you can afford it, you can pick up a Line 6 XT Live, which runs around $250 or less used. If you pick it up used, you can likely move it later on down the road and make back your money. One good thing about the XT Live is that, should you ever choose to, you can actually take it with you, run it out to a sound board and effectively use it to play live gigs. It's metal, so it's relatively sturdy.
This is different than the UX3, which is the newest version of that product line. Some of the XT Lives that you will find used, like the one I owned, contain software packages that the owners have paid for that contain more amp and pedal models. Once you get used to working it, it's a pretty flexible piece of gear that you can do a lot with utilizing the free software from Line 6. In a way, I kind of regret getting rid of mine.
2) I currently use a Line 6 TonePort UX2 that I picked up at a pawnshop for $50. The free software comes with some preamp, pedal effects, guitar and bass amp models, and some mic simulators. The software is free and, if I recall correctly, supports Vista 64-bit. You can play around with the chain of effects and the effects, while obviously not as nice as actual pedals, are pretty adjustable. If anything, it allows you to get an idea of what an effect does should you choose to pursue that effect later on down the road.
http://line6.com/podstudioux2/
3) If you have pedals, which Ame mentioned having, M-Audio puts out a MobilePRE USB which is a simple USB preamp that, IMHO, sounds pretty good. It has both XLR and the standard 1/4" guitar cable input as well, which a signal boost.
I had to move away from it because I got a computer with Vista 64-bit and M-Audio didn't support it at that time. Now they do. Man, I need to pick one of those up again. The MobilePRE is great for recording mic'd amps, even at apartment levels. I'm sure it would sound good for louder recordings, but I can't do that where I live.
I'm pretty sure that you can pick these up used as well for under $100 (I sold mine for $50). You can buy a FastTrack USB for $70 new at Guitar Center
http://www.guitarcenter.com/M-Audio...ter-Recording-Interface-102935160-i1154546.gc. If you don't have your own effects or don't know how to work effects and play with .wav editing software (such as Cool Edit Pro 2, among others), I wouldn't suggest this.
http://www.m-audio.com/products/en_us/MobilePreUSB.html
4) Presonus put out a tube preamp called the TubePRE that can also be had for about $50 used. I currently have this (and I'd forgotten about it), but it doesn't hook up via USB. So, it's not REALLY relevant but figured i'd include it. It has a single input with gain/drive controls. It has a single 12AX7 preamp tube, but, honestly, it does little to make it sound more tube like for guitar. I do notice vocals sound better through it. I'd go with the M-Audio MobilePRE, get the ability to record utilizing more than one input, and forget about this one unless you're looking to warm up vocals a little bit.
http://www.presonus.com/products/Detail.aspx?ProductId=16
5) Korg put out a little effects processor called the AX3G a few years ago (it's discontinued now). It sounds pretty good, though is a pain in the ass to use...so much that I rarely use it except for recording a clean electric sound. The effects are pretty good too, once you get past the initial hurdle of tweaking them. I once recorded a quick demo of an old song of mine using a heavy phaser on the rhythm guitar and a rotary/leslie effect on the "lead" guitar...think the verses on Black Hole Sun, but a must faster effect.
You can find it at
http://soundclick.com/share?songid=6224433 (just promise not to laugh at the other songs you'll find on that profile...I improvised or did them all in one take). This was recorded by plugging the AX3G directly into the MobilePRE USB and playing with the amp settings a bit. Not a bad clean sound.
Korg came out with an AX3000G that's been discontinued. It appears to be a bigger version of the AX3G and some demos on YouTube don't sound too bad. Apparenly, it breaks under heavy use, but if youre not rocking out and stomping all over the place, I assume it won't. I might have to check into that.
So all of that being said.
The TonePort has been good to me for recording acoustic guitar and bass, though I'm not too terribly impressed with it for recording electric guitar. It sounds good on the computer and headphones, but just doesn't translate well in a mix. It's likely because I haven't sat down and REALLY tried to make it work. I missed my M-Audio MobilePRE so much that I didn't want something to replace it unless it did a better job. That being said, the models do sound decent enough in headphones, especially after you tweak them.
The signal boost feature on the MobilePRE is far and away better than the Toneport. Perhaps my Toneport is broken and it's not working right. Perhaps I just don't know how to make it work. Who knows?
That might not answer any questions asked, but, as a bedroom/apartment player, these are the options I've looked into for songwriting and/or recording options. I'd take my Fender Deluxe Reverb Reissue mic'd up over them all any day, but my neighbors wouldn't think too kindly about any extended use of that.
Feel free to give me a PM if you have any other gear related questions. I'll do my best to answer.
