It is not worth unlocking the Bear collections as all it does is shorten the coin regeneration by six seconds.
Endless Coins
If you combine the 'Straight Push' hint with the 'Gems Collection' hint you will have endless coins to play with at the end of the game. All you then need is patience and hope you are lucky and receive the prizes you don't have so you can unlock other collections.
Gems Collection
If you unlock the Gems collection you will get three coins for every one coin that you manage to collect.
More Coins
If you set your iPod main clock a few hours ahead you will have more coins.
Whistles
If you are lucky enough to get a whistle you will never have to worry about losing prizes that fall off the gutter. The only thing with whistles though is they do not come by often.