See the reply here:
https://bitcointalk.org/index.php?topic=2134900.0Only Sidehack is still making USB stick miners with modern chips. You'll probably pay between $75 - $100 for one from a reseller. It'll get around 15gh/s. If you want the equivalent of an Avalon, you'll need about 45 of them.
Another option is to get an R4 from Bitmain - this is relatively silent, but hard to find and more expensive. Expect around 7.5 TH/s Between $3,000 - $4,000 on eBay.
Finally, you could get an S7LN from Bitmain. That'll be less powerful, but it can be undervolted to run almost silent as well. It'll only pull 2 or so TH/s. I've seen them as low as $500 on eBay, but with the upwards price they're getting to be around $800.
If you are price sensitive, you want the most dollars per TH/s.