I would say find good goalkeepers that right now are on the bench but have a big chance to become 1st goalkeeper next season or make a transfer. You will need some patience but they should become more expensive and usable in case it does happen. In Belgium I'm eying Ortwin De Wolf (currently 2nd goalkeeper of Antwerp but he wants to play again almost making a transfer last winter), Warleson from Cercle Brugge who now is 2nd goalkeeper but should become 1st goalkeeper next season, Van Crombrugge who was 1st goalkeeper of Anderlecht but he has a contract that is too expensive and 2nd goalkeeper Verbruggen got his chance which he is fully taken to the point where he got linked to bigger teams. Van Crombrugge will either become 1st goalkeeper again or go to another team next season.

Goalkeepers that play used to be a lot more expensive and I would say right now are quite affordable.

Good Luck!