Logitech make a great mouse here Its what i am using now and you can get it on sale for <$20 I got mine for $23 a few months back. I also have 2 MS opticals. but the one (Explorer 3.0 USB) was a little more. Dont know how much it goes for now. I am loving the Logitech though, I would recommend it to anyone. Good for right or lefty's too.
The majority of people I know go with Microsoft and Logitech mice, but me, I like A4Tech. They may be a lesser known brand, but their mice are pretty good quality and cheap too. I use their wireless optical mouse and it set me back about $30USD.
I used to swear by my MS Intelieye Explorer. I swore they would have to pry it from my cold dead hand to get it from me. Then I tried a Logitech MX500. Now the Explorer does closet duty and they will have to pry my MX500 from my cold dead hand if they want to take it from me