That dinosaur set is £23 here - lots of £££!!! Looks fab though. It's actually a stage more difficult than the set DS did the other day which was a 'first' set like this
http://www.amazon.com/My-First-Sticky-Mosaics%C2%AE-Pets/dp/B001THPZMQ/ref=pd_bxgy_t_img_yit wasn't the vehicles set we had but it's the same make and level. If you look on the box cover you see the guidance on the picture is a coloured shape, there were 3 shapes for each sticker colour so the right one is chosen each time. The dino set is stick by numbers, I know DS would love it but I'm not paying that for 1 days play.
The set we got is £8 on amazon and that vehicle set is £10, much more expensive than the bargain I got. Even on The Work website I saw it was more like £8 and I got it down to £2 in the shop!!
I would certainly look at buying these again but will be keeping an eye out for another bargain. I've been looking for a few months for these actually and always backed off because for a 'use once' toy they are quite pricey if they are not in the sale.
There must be 100s of way to do similar crafty type mosaics without buying these sets - but I know for DS he wouldn't sit there cutting up pieces to glue them on with glue stick etc, he just won't.
You can get just the stickers (foam or sparkly etc) like this
http://www.amazon.co.uk/Self-Adhesive-Foam-Mosaic-Squares-Pack/dp/B00702S6NO/ref=sr_1_9?s=kids&ie=UTF8&qid=1407089238&sr=1-9&keywords=mosaic+stickersand find or print a colour picture which they then add to with the stickers. Or a blank colouring page where you number the colours yourself or print of a paint by numbers but do sticker mosaic instead of paint.
I know DS really liked that he had to put the triangles and squares at a certain angle, which is drawn on the set, it added to level of concentration required and also guidance given iyswim.