Gosh that's a good question!
It depends what player's are on the sticker sheets I'd say, so it's hard to have a definitive answer.
I'd say we have an active test for the following sticker sheet live on eBay
Find many great new & used options and get the best deals for RARE PANINI FOOTBALL 85 UNCUT 12 X STICKERS SHEET CHRIS WADDLE ROOKIE LIVERPOOL at the best online prices at eBay! Free delivery for many products!
www.ebay.co.uk
I'd guess 12 player stickers could be sold for £1 each on eBay if listed separately. Maybe the Liverpool ones on this sheet could go for more.
If auctioned off as a batch of 12 different stickers it may only achieve £3-5 (sometimes less)
I don't think this sticker sheet will reach £12 so I'd say individual stickers are still better as most would prefer Messi rookie
(sorry to use the rookie swear word!) on a single sticker than on a sheet!
Hope Austria is good, I miss my trips over to see friends in Graz.