If you are strict on budget cant overshoot it by any chance, then a logitech mouse or microsoft optical mouse (cost varies frm 375-450) is the best bet , once u get comforatable with those u can really pawn ( m serious ) , the best part of these mouse are they dont skip even at low sensitivities whereas 90 percent of other optical non gaming mouse will skip when u make fast movements
Increase ur budget. Yu get useless gaming mouses for 400 bucks. Save up some cash and get a Razer Deathadder or MX. Yu can use it w/o any harm for 4-5 yrs.
You need to get a good gaming surface to compliment the gaming mouse otherwise its of no use. You may ruin your mouse feet if you don't use proper mouse pad
Some one has to be really good hearted to sell a mx-518 for 500-600 bucks unless its arnd 2 and half year old ,
I agree mpad is a must but if u have budget constraints its not a absolutely neccesary to buy a gaming one , a gud enuf mpad starts at 25 rs itself (surface brand mpad trust me its one of the best mpads i have ever used and it has a cloth surface ), and from gaming mpad perspective if u have budget to buy one then there are rantopads which retail for around 350-400 but i would suggest you to buy a mx-518 and a surface mpad over a Microsoft Basic optical mouse or the gigabyte gaming mouse and a 400 rs + gaming mpad
even worn out, 2+ year old MX's sell for 700ish. best bet is to get a dead out of warranty razer for 600ish, and try repairing it (not that hard if you know soldering)
For an ultra low budget you have the following options..
Microsoft Basic < Gigabyet M6800 < MX518 < Razer DA
The MS Basic is very good beginners mouse .. light weight and quiet sturdy and you can easlily play on a hard table-top without a mousepad too.
Pair it up with a cheap 20bucks cloth pad and you have a deadly combo.
You can start saving up cash an pick up a MX 518 in a couple of months.
I would recommend buying a product with warranty coz you would need to RMA it once in its lifetime.