Blocks for a lug rig

[skylark]

I am putting a lug rig together for my 16' sharpie/sailing canoe project.  I need two double blocks and a few single blocks for 3/8" line, which will be the sheet.  The rig is similar to a junk rig but there is only one batten (reef point) and I do not plan to attach the sheet to the yard, just to the boom and batten.  This is somewhat experimental and if it works I will move from a polytarp sail to cutting up an old sail I have to make a dacron sail.

My question is, are there any blocks that are relatively inexpensive?  Would you make your own blocks to save some money?