The world of budget, portable audio interfaces is in great health. There are many options available today of very high quality. Preamps and converters in budget interfaces have reached a level that would have seemed impossible at such a low price point 10 or 15 years ago. If you don’t need to record a huge number of inputs simultaneously, there’s no reason you can’t make great recordings these days with a $200 interface (or even cheaper).
Even though it’s harder than ever to go wrong, I’m going to focus on one of my personal favorites: the Creative Labs E-MU 0404 USB 2.0. It’s been around for quite a few years and is actually discontinued now, so you may wonder why it’s even worth considering since I just mentioned how many great options there are these days, but these interfaces are pretty easy to find and I feel they’re still one of the best options out there. I even found a retailer selling one in a never-opened box less than 6 months ago. If you check eBay somewhat regularly, you shouldn’t have a problem finding one, and I believe it’s a worthy choice even if it has to be purchased used.