So its a Groupon deal - but this one is actually good!
If you are going to the great Dorset Steam Fair this year then buy this deal. Groupon (like last year) are selling the tickets at roughly half price when purchased in advance so its a good saving.
On top of this when we went last year there was a queue which must have been a good 40 minutes long to pay and get in. With the voucher not only do you get in for half price but you don't have to queue.
This got pretty hot last year so hopefully it will do this time too.