hey mate i found my exact amp and bass on ebay if u wana see it but do u know how much a new fuse costs and how i can prevent it next time?
A new fuse might cost a buck or so.
If it IS a blown fuse, which remains to be proven, then the question is what made it blow? Once in a while it just happens seemingly randomly. But if it blows again, there's definitely something shorted in the amp, drawing too much current. Old filter capacitors in the power supply are a common problem that can do this.
"A cheerful heart is good medicine."
This has probably been figured out already but that is obviously a circuit breaker or 'reset' button which serves the same function as a fuse, (and is labeled 'fuse') which is to protect the internal circuitry from current overloads. If the breaker has tripped then you push the reset button, here labeled as 'FUSE' button and that resets it. A circuit breaker is simply a reusable fuse, instead of burning out an element to open the circuit it has a thermal (heat) actuated spring gizmo that opens the circuit (thus not allowing any electricity to pass through- like a disconnected wire- closed circuit allows electricity to pass through- an attached wire is closed circuit- unattached is open circuit) Sometimes you have to push really HARD to reset it. Push hard until you hear it 'click'. Remember that about breakers and reset buttons, sometimes you have to push hard to reset them. When a breaker like this breaks the circuit the button will stick out further. Push the button in HARD with the amplifier OFF until you hear it click. When you turn the amp on it should be OK. If the button pops out again right away you have another problem, a short somewhere, possibly in the guitar cord, is it a junk cord? I'm not sure if a shorted cord to the guitar would trip the breaker switch but I assume that it would, or faulty or lose wiring in the guitar., or a bad power wire to the electrical outlet. it is possible but unlikely that the breaker switch itself is burnt out. It is also possible that there is another fuse in the system (although it isn't listed so that is not too likely) but if so it should be easy to find.
Chances are you just have to reset the breaker. If you abused the amp and pushed it beyond it's limits to cause the breaker to blow you should be a little bit nicer to it next time. Without the breaker switch or fuse you could be facing worse problems like a blown speaker or blown amplifier, so try to be nice to your equipment and don't abuse it to the extent of blowing it up.
Whenever you ask a question like this it would be most helpful to include the most elemental information like what amp make and model you are talking about?