you'll have to pay the price and deal with the shops but once it's legal and you find yourself in there daily for a period of years (I'm very loyal to my shop) you tend to get better deals down the line.
I get better than online prices on a lot of stuff at the mom and pop I shop.
By all means I can save $2 a stone at my local shop.... and stones add up quick....
But ballasts, hoods, inline fans.... Amazon.com I got my last hood @ the shop out of need for immediate use, and @ 20% off, it was still only to 'comparable' prices with the same model online, with shipping.
I get my day-to-day shit from the shop, but major items, I check the price.... then I scan the UPC with my Amazon app and see if I can get it prime cheaper..... Some things I will even ask if they can match the price I find, if so, i buy it. If not, still need hydroton, air stones, fittings and hoses, seed starters, etc.
If you have a continuity tester you can test the fuse. Hell I can think of several stone age ways to test the fuse. Sometimes in a bind back in the 70s you could wrap a blown auto fuse with foil although I wouldn't advise it.
I have had to rig this shit once, with a piece of speaker wire tho... my woman thought I was crazy "Just trust me, this is how electronics work, it will get us to the next exit"
Just two chime in, if you have a hydro shop near you there may be someone there who could fix it. The guy in my shop repairs ballast and he's nice enough to not charge you if he can't repair it. Maybe something you could look into if you don't have success on your own.