I have found that these are cheap to make and easy to use.
1)Go to the local sport shop and get some golf tees,the kind that has 2 parts to them.
2)Remove the top part where the ball rests on,this is the part that will be used,and you should be able to just pull them appart
3)Drill a hole all the way through ,if you removed the spike properly you hole is half way done already as its embedded in the top part.
4)Using a sharp hobby knife or blade cut along the one side of the tee,this is where you would insert the line,dont cut it straight down but at an angle