Here is a tip: do it yourself. It is actually pretty easy to do.
Halyards are pretty easy to replace by stitching the new line onto an end of the old line and pulling it through. David is right that if your sheaves at the top of the mast are messed up this can be much more difficult to do.
Most of the lines on your boat are easy to replace but the line may cost a significant amount of money. I'd guess that you could replace ALL your running rigging on a Tartan 30 for under $500 in materials.
I'd consider getting this sewing tool to attach the 2 lines together: BAINBRIDGE INTL Needle at West Marine
be smart about burning the ends of each line you cut.