I will spend some money on this game regularly if it brings fun to the table regularly. I however, will NOT spend $15 for another quest line like the dapper wall-e line. Wall-e is probably the only character I'd do that for. I'd probably spend $5 without huge regrets.
I'd also be wary of spending any form of subscription model until they get their QA sorted out. Every release has some pretty unacceptable bugs. (companions blocking your way, all the passion lily's being red, dark castle portals being so far in front of the doors you have to go fish, the true random on scrooges shop) I understands the occasional putting a fishing target on land too much but their QA/Dev team sizes are WAY to big to let this kinda change go out, especially considering they don't hotfix.