I'd play and a $10 WIS gift card has always been good in the past. I would be with something more than $10, but that is what I have seen in the past. Do you have any other details yet? Will it be roto or H2H? Also, is there a reason you are using Yahoo? ESPN has much better fantasy tools.
Last thing, if you decide to go the WIS gift card route, admin will hold the $ until the end of the season and will distribute it at the end of the season as you direct. Just send them a ticket and confirm. That is what Danmam does for his fantasy leagues.