I have such horrible memory I never played much back then when the game started but I swear dark forest is lvl 8 to go in so once you reach L13 for balefort which is after dark forest, you don't gain exp in forest haven at 13 so you had to buy dark forest .. So I think thats when you had to pay to continue.. Not sure if the lvls would have changed if so it could of been lvl 8 then :/