M.L.
Look at etsy for for items that you make and charge a variable rate based on the average pay and what you can gain. Also, the thing about craft fairs (I have done many, as well as sold to stores) is people will want to bargain, or have bulk discounts. So, you have to decide if you are going to go down a few bucks, or not. One thing we always do (and many other vendors) is the last hour and a half or so, put up a sign that says, buy one get one half off, or 30% off everything. ALSO... having a cheapo item is awesome. It draws people to your table and makes add on sales. Like little bookmarks/magnets that kind of stuff.
For me, I double my cost, then I add on time. for a $3 item, I would make it $6, then add on about $10 or $15. So that minkee lap blanket could go for $16-$20. Think of it this way, 50% off should be your wholesale cost. If 50% off isn't worth it to you, then you need to raise your prices.
It's also all about presentation. Tie an adorable silk or grosgrain ribbon or chunky piece of tulle around a rolled up minkee blanket, and people go nuts over them, more than they would if they were just lying flat on the table. Of course, leave a few flat so people can inspect size/quality...
car seat covers, usually from $50 to $100, that gives you a lot of room to play with price and mark down if needed:
http://www.etsy.com/search/handmade?search_submit=&
q=car+seat+covers&view_type=list&ship_to=US
minky baby blankets, mid $30's on up is average, depending on size:
http://www.etsy.com/search/handmade?search_submit=&q=...
minkey little burp cloth type sized lovies ,about $15 average:
http://www.etsy.com/search/handmade?search_submit=&q=...
