If I understand right, when you say aid, are you refering to the thing on the string your release attaches too? If so here is what I choose:

I would stear clear of the metal ones. They make a wierd sound when you shot. I use a simple loop. Cheap and easy. I have heard people say they are trouble to get the release on, I have never noticed it. I have been using them for a long time with no problem at all,.

If you are looking for a cheap release, you can find a good one in the $20 to $30 range. Split fires are great and run aroung 25 bucks. Lots of caliper type in the same range.

Little hint, keep your releases lubed with dry graphite and it will always work fine.