The prices listed here on the disboard are $38.34 at the gate adult and child. To purchase ahead of time $29.50 adult and $26 child. We usually purchased tickets ahead of time the ticket brokers like ticketmania and undercover.tourist etc tend to put these on sale fairly often.
There are the toys and cds that you can purchase after making them if you like. You can just make them for fun and not buy. The cds aren't actually karokee, you put the song together by picking the type of music, the lyrics, the type of voice etc. You can then listen to your creation if you want to buy a copy you can print out the song. You don't get to sing on the cd.
The only other place that you have to pay is one area where you can win tickets from the games and then trade them in for prizes. This is a very small area and we just avoid it with our kids.
I got such a kick out of a kid from my son's class who went to Disney when he was 6. When I asked him what his favourite thing was at WDW, he said it was Disney Quest. He was so excited to tell me about all these arcades and they're all "free''

I guess the $30 dad paid at the front door didn't count. So cute.
My son and husband love Disney Quest and go everytime, this last time dd and I skipped it and went to BBB while they were they. The place just gives me a big headache.
That rumour about Disney Quest closing has been around for a couple of years but I've never seen anything officially announced.