The budget is up to 100$ . No additional buttons is needed, a regular mouse, but durable and responsive. At the moment I own Roccat kone XTD, but after a year (or a year and a half) of use, it began to hang.
i just bought the G305 mouse and i ABSOLUTELY love it.. its lightweight with a hero sensor so its phenominal for FPS gaming, better than the heavier G502 according to most FPS gamers, and what i really like about the G305 is its size and shape which makes it very comfortable and very easy to use either claw or fingertip style.. its also pretty well supported by the community that uses them, with a number of 3D printable shell mods you can download.. some get the mouse under 70 grams with perforations like you would find on a finalmouse
i was going to get a G502, but i didnt like its "ergo" shape which sort of dictates how you have to hold it and wanted something a bit more flexible
the G305 is also wireless for under $50 and has an input lag/latency equal to, or even faster than a wired USB connection