On the plus side, your winnings from the free spins are subject to a relatively small wagering requirement of just 20x, so there is at least some possibility of actually converting these spins into a withdrawable balance. I managed a balance of around £40 from my fifty spins and chose to increase my bet up to 0.75 per spin and prayed for a bonus to drop, which it did, and after winning around £130 from that feature I was able to build my balance up to over £200 however by the time I had cleared my wagering requirement I was left with a remaining balance of just over £50. I felt very much demoralised because of this, seeing as I had deposited £50 in order to get the free spins in the first place :(
Free spin based bonuses just don't seem to work out very well for me and I chose to withdraw my balance of £57 at this point so that I could re-deposit and take advantage of the 50% match offer which is available when a player makes their fifth deposit. I wish that Slotty would allow players to choose the game they wish to use their free spins on rather than forcing all players to choose Slotty's "game of the week", but as things stand I would highly recommend waiting for a game such as Jack Hammer 2 or Reel Rush to come up as the GoTW, as your free spins will be worth a lot more on those games than they would on Starburst.