I get the feeling you'd have really good luck searching Ebay for "microphones" and focusing on finding one low cost mic. You'd be surprised what I've gotten away with having just one microphone for a while. You just have to do 'a lot' of recording and be happy with having only one mic on each instruments (including drums). This turns out to be really good practice for learning the best places to put a microphone and pays off very well in the long term. Since you're really price conscious you'll have spend a ton of time instead looking for deals. Buy used! Check local pawn shops and music stores for whatever used mics they have. Talk to them. Cool shops will really try and help you out if you're new. You might just get one for free

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Here are my mic recommendations while looking around:
1) You're going to have the most fun with XLR mics. Time to step up from the cheaper computer mics, I say! Also, focusing on XLR will help you out while searching online. If you're new to mics this advice will help out a lot.
2) My first mic was a dynamic mic. I've never had any problems with this

And I still use it. Pay attention to dynamic mics while searching online. My perception is that they tend to be priced lower than other mic types, like condensers.
3) Without a doubt keep in mind that you'll still need enough money for an XLR cable. Again, buy used.
4) Let us know what you're planning to plug this mic into. Search the forums here to see what other people say about your existing equipment. It'll make things easier down the road.
Best of luck,
Shaun
P.S. I usually double-check my replies before sending but I've gotta help a friend out with a blown tire right now. Egads! Hope the rest of the forum can clear up any goofs in this post while I'm gone. Cheers.