i take it that you are referring to the beyerdynamic dt990 pro 250ohm which is available for about $200? and not the more expensive premium line which is available in a 32oh version not requiring an amplifier?
the dt990 250ohm are notoriously hard to drive so you will want a decently powerful amplifier.
what type of amplifier you want depends on if it needs to be portable or not.
the schiit magni for $130 does a stellar job of driving the 250ohm cans and would be your suggested route without breaking the bank.
if that is too pricey the fiio e10k can be paired up with them and can certainly drive them fine though not as well and might struggle a bit at high volumes and with bass boost on.
if your use will be pc only and you have a...