what does it cost for a transmission slipping problem ?

You'll most likely need a transmission rebuild to fix it. I'd guess between $2000 and $3000. It may be possible to find a guaranteed used unit, ask your mechanic about it. Get the transmission diagnosed at a transmission shop or a Saturn specialist. If you want to find a Saturn specialist, here's our directory link for you: https://repairpal.com/saturn-repair-in-upland-california