I used to do all kinds of swaps, from fat quarter swaps to block swaps to secret santa swaps. I don't do them anymore. I have gotten some very poor quality fabrics in fq swaps, some very poor workmanship and horrible color choices in block swaps and a bunch of dollar store junk in secret santa swaps. Some of the swaps were even in local guilds and not mailed swaps.
In our small guild we did a log cabin block round robin. I wanted purples on the dark side and yellow on the light side. I got just about everything but purple and yellow. Except one strip on the dark side is a purple on yellow plaid.
We did one block of the month swap and there are two members that I never did get blocks from. I made extra blocks myself and just put the quilt together.
I was in one internet block swap that it took almost a year from the time the swap started to get my blocks back and it was only a four block swap! I ended up tossing one of the swapped blocks anyway because it was very poor quality fabric and making another one myself.
As for fat quarter swaps, I got tired of getting cheap fabric back when I sent in "quilt shop quality" fabric. If you can only afford walmart fabric maybe you should save the money you'd spend on postage and buy better quality fabrics on sale. If you're on the internet you have access to thousands of quilt shops with tons of sale fabrics.