My sails don't yet require replacement but when I bought the boat last year I did investigate costs. (Mine is a Nordic Folkboat with a 3/4 rig but I wouldn't think that would make a very big difference, similar amounts of labour value being involved.) Crusader Sails quoted me about £800 for a new main, 250 for a No 2 Genoa. More recently I have been looking into a roller furling headsail and Owen Sails quoted about £800 - they do make very fine sails but that does seem a bit steep.
We have a Vega so sail sizes should be similar.
Whilst the £800 quoted for a Main Sail sounds a lot, I'd still suggest that the £450 asked for a 'newish' pair is very good value.