the best cheap (dome) keyboard is still the sidwinder x4, cheap mouse the logitech G400. you cant go wrong with either of em.
surge protectors are only of use if you have a high amperage single rail in your psu. if you have a modular 1 with multiple rails the surge protector wont trip before the psu's own over voltage protection trips (assuming it has it).
as for ups there only of use if you can spend a fair whack of money on em as the smaller units will only give seconds of reserve current which makes them pointless for most people. they will however stabilize current from a dirty output that suffers spikes and dips as long as there not to severe.
for a home pc you will be looking at around 1kw to give you about 100 mins of safety if your pc is idling but maybe less than 6 mins if your gaming.
the bad news is get that kind of margin your looking at around £400-500 which might be outside your budget.