Txnub, I understand about the cost, but even a decent .22 mag bolt action rifle will be $250 and up. Mostly up. I've tried 3 Marlins, but none of them shot better than 2" @ 100yds when I got them. I tried 11 different brands and types of ammo in them to give them a chance, but gave up and got rid of them.
I haven't tried a Savage, but you're looking for a semi-auto anyway, so In my opinion, the discontinued Ruger 10-22 magnum is probably the best bet, but be prepared to spend at least $500 for a used one. If it's accurate, you're way ahead of the game. If not, the generous application of more money for a premium barrel, trigger, etc, will make an accurate rifle out of it. Unlike the 10-22 l/r's, the 10-22 magnums have steel receivers, a big advantage to me, and a good basis to assemble an accurate semiauto rifle on.
Years ago, H & R made a semiauto .22 mag, also discontinued, but I don't know anything about them.
In my opinion, the long-discontinued H & K Model 300 is the best of the semiauto .22 mags, but they're in the $1200 - $1500 range now, if you can find one. Also, clips for them are very hard to find, and are around $75 - $100 each.
To sum up, there isn't much avilable in a good semiauto .22 mag, but like Dust said, I also would search Gunbroker, Guns America, etc. to see what is available and for what price.
Good luck, Tom