DIY $75 Large 18x9 Foam Oval Track
Foam Tiles:
Cost Co which is like Sams Wholesale, has a pack of Six with edges for $10.99
http://www.costco.com/
Use the edges and glue them vertical and cover with VINYL J MOLD(like drywall corner mold from Home Depot or Lowes).
VINYL J MOLD $1.19 for like 12 feet
It slips right over the extra foam edges you get with the tile packs
http://www.tamlyn.com/pvc/jmold.html
Or Do not cover the barriers and just make foam rails. But foam rails stop the cars too much, but they do keep them from getting scratched up.
This is my first RC track.... may be some redesigns later.