E.M.
call an appliance repair store. they can give you a rough estimate.
ours pooped out a couple months ago. it was the pump or the control panel and it's 15 years old. appliance repair said don't bother - they wouldn't come out because they'd just be taking our money.
for a variety of reasons we decided to wait until after christmas to replace. well, not sure we're going to now. it was a big surprise but doing dishes by hand hasn't really bothered us nor has it taken that much more time. it's been good together time for talking whether it's my husband and me, the two kids or a kid and parent. it's been good for the kids too to do the dishes and learn how.
anyway - $400 to $2000 for new dependent on what you want.