Yo TA814! Here's a radical suggestion that's gaining a little local popularity. I picked up this link right off the annoying sidebar next to your post:
http://www.gosale.com/4980667/zoom-h4n-handy-recorder-h4next?gclid=CLGeobWYj6ACFQ8Vawod2j8beA
My suggestion is
Zoom H4n
What is it? It's a standalone 4 track flash recorder *and* it's a USB interface, right in your price range. A little glossary here- Many people here bristle a little at the idea of a standalone recorder being called a "studio". We understand that a studio is a facility, with acoustically prepared space, and all the major pain in the butt that goes with that. We often use the acronym SIAB (studio-in-a-box) or just standalone. That said, I believe that there is no better machine in your price range for your purposes than the H4n.
OK- some background- I am a small time recording artist and I own a studio that is on the dividing line between a pretty kickass project studio and fly-by-night pro. I'm no engineer, but I've got about $35,000-40,000 sunk into gear. One of those pieces of gear is the H4n, which I bought about 9 months ago to upgrade an older micro-recorder that had become obsolete. So here's what it does:
First, it's a standalone 4 track recorder with 2 built in small diaphragm condenser mics. It has 2 XLR/1/4" combijacks that are switchable from mic to line level input, and the XLR's have available 24V or 48V phantom power to power condenser mics. It also has a 3.5mm mini-jack for stereo mics designed for minidiscs, camcorders, etc. This disables the onboard mics. It records on SD cards, like a camera card, and supports up to 32 gig cards. It comes with a 1 gig card, which is fairly useless. 32 gigs will give you 11 hours or so in stereo at 24bit/96kHz, which is more than any sane person will ever need. It is powered by 2 AA batteries or a supplied AC/DC converter. It can record 4 separate tracks, either by using the 2 combijacks and the onboard mics, or by overdubbing the tracks one or two at a time.
It records in MP3 from waaay stupid compressed to high resolution (as MP3's go), or as WAV. files, which is what most computer recording software wants. It will do up to 24bit/96kHz in stereo, or 16bit/44.1kHz (same as a CD) in 4 track mode. In 4 track, it has a whole bunch of effects-reverbs, compression with adjustable parameters, metronome, guitar tuner, and some rudimentary guitar and bass amp modeling. It also comes with Cubase recording software, which is handy, because...
At the flick of a switch, it becomes a USB powered recording interface. So- you can dump stuff that you've recorded into the computer for processing with Cubase or almost any other recording software, or- you can record straight to the computer, using the computer's memory and processing power.
OK, that's what it does. Here's why I think it meets your needs:
1. It fits in the palm of your hand, or in a guitar case, so it's ideal for taking wherever you want to go to record something. It is the PDA of a recording artist. So when you upgrade to that 64 track Pro Tools HD rig, it won't become useless. It follows me wherever I go, for a headphone amp, a musical thinkpad, or to capture that steel band on the beach. It's small enough to be there when I want it to be.
2. Right off the bat, it adds 2 mics to your collection. So you could play acoustic into the onboard mics, and simultaneously sing into your 57 on track 3, or lots of other combinations.
3. It does everything that a standalone recorder does, everything that an interface does, runs on batteries,and has a couple of mics thrown in.
It's fair for me to point out the downsides- You only get 4 tracks at a time, and only 2 of them let you plug in whatever you want. In your price range, that's about what any other interface will do. For about $350,
the M-Audio fast track ultra would get you 4 mic inputs, but it's just an interface- no recorder, no mics., more money. Secondly, the preamps are not that great. Neither are the preamps in any interface or standalone recorder in your price range. Last, it is made by Zoom, owned by Samson, which is known for building cheap bottom feeder gear. Its predecessor, the H4, had serious "issues" and I wouldn't buy one at any price. This machine has given almost nobody any of the problems that the older units had. It looks like they really went to work to make the H4n work the way they had originally planned for the H4.
I learned multitrack recording on a pocket recorder, and I wish they'd had a machine like the H4n when I started. In conclusion, for the record, I don't work for Zoom, I don't sell recording gear, and I don't really care if you buy one or not. It just seems like it meets all of your immediate needs in one handheld device. Best of luck with whatever you wind up with.-Richie