So, your WMO just died. You are a cheap cunt and want a bargain (less than 20). You need a mouse that has a newer (flawless) sensor and has 500/1000hz default polling rate. Here's some options:

Candidates:

Anker 2000 DPI Mouse - http://www.amazon.co.uk/gp/product/B00CBQO930/
16. Avago ADNS 3050. Omron Switches.

CM Storm Alcor - http://www.amazon.co.uk/gp/product/B00IMIK8IQ
24. Avago ADNS 3090. Good IME 3.0 replacement. Hopefully there is a better price for this out there. 3 year warranty.

CM Storm Xornet - http://www.amazon.co.uk/Cooler-Master-Storm-X...B00608KSPI
15. Avago ADNS 3050. Omron Switches. 3 year warranty.

Logitech G100S - http://ebay.eu/1rgo5mE or http://amzn.to/1tc14Pm
12 (eBay) / 16 (Amazon). Highly regarded. 2 year warranty.

Perixx MX-1000 - http://www.amazon.co.uk/Perixx-MX-1000-Progra...B008YFXG9K
13. Avago ADNS 3050. Omron Switches.

SteelSeries Kana V2 - http://www.ebuyer.com/620083-steel-series-kan...ouse-62262
18. Well built. Takasta Review - http://bit.ly/1qfL0YX

eBay Zowie EC1/2 eVo
Astz! says you can get them for 20 euro if you wait for them to pop up.