Mouse Nerd here.
If you're looking for anything similar in shape they're all in the 40-50$ range. Most of the suggestions are good in terms of budget but you'll most likely find them incredibly uncomfortable and will take some time to get used to due to ergonomics and weight.
Seeing as you don't want that to happen really here are my suggestions as when it comes to mice the most important thing in my opinion for FPS games are shape and weight.
For another 10$ you can grab the G402 @ 40 USD with Amazon Prime does use a slightly older sensor, AM010, but most are fine with it as it was the same sensor in the G100s, similar weight and shape.
If you get another $20 you're in range of the:
- G403 Wired @ 46.99 USD with Amazon Prime HOWEVER it does weigh a lot less than the G602 and the shape is a bit different but is ergonomic.
- G502 @ 45.99 with Amazon Prime closest to the G602 in terms of ergonomics and weight, probably top option.
- Both of which use top of the line Logitech Exclusive PMW3366 Optical Sensor
edit: If you don't have prime, you can sign up for a month for free if you haven't already. You can also make a new email and still get prime for a month for free.