I bought BIG muff and bad monkey(stock) but I dont know if they are any useful on stage playing because assuming they are made for guitars someone tell me please so I can return them back quick.
I have the Russian Big Muff Pi and the Digitech Bad Monkey, and I use both of them live with little or no bottom end loss. The Bad Monkey does suck out a little bit of you really deep lows, but it can add a lot of low mids, so it's not as noticeable. The Russian Big Muff has TONS of low end.
You might be able to use them to fret with, but they're probably too large to use as picks. Instead of using them to play your bass with, try using a chord with 1/4" jacks to plug your bass into the the "input" and then another from the "output" to your amplifier. Then if you "stomp" on them they should make funny sounds. If you have anymore questions feel free to ask, I'm here to help.
Smart-A$$ OP, Sure, they're useful, but you have to find your use for them. It can be difficult sometimes if you're using them for original tunes, but sometimes necessary when you're looking to cop the sound/tone of cover songs. Good choice, by the way, as overdrive and fuzz are a couple of the most-used bass effects.
Plug them in and mess around for a while. If you dig what you hear enough that you don't miss the money, then they're keepers. If not, return/sell them and use the money for something that you DO like. By the way, it would probably be useful to search around here on TB before more shopping. People here can give you some general information and opinions on what you're looking at. But they're opinions only. Use your ears.
No. I don't know why we bother. I have no idea why FX is the 3rd busiest subforum after BG and OT. Total waste of time.