2 comments:
1) 2x2 tiles in colors red, yellow or dark tan (likely in that order) are the cheapest on BrickLlink. The 1x8 might also be affordable as other members suggested. For 1x8 the cheap colors are likely to be blue, white, black, red (in that order?) There is also the 1x2 route with colors including lime, bright pink, and dark purple, but I don't really recommend the 1x2's unless you can make a cool pattern combining them (much more work than the 2x2s).
All the pieces mentioned before have been widely available in the PABs in the past years and there is a surplus of them. Also available were 1x4s in green and reddish brown I think those will be more expensive.
No guarantee that you can find any of them in the current PAB selection when you go to the store in fact it is likely you will find completely different stuff maybe other tiles and colors, maybe nothing relevant at all, best thing is to call the store and ask.
2) This is VERY important: When gluing the baseplates to the table make sure to put some tiles/plates/bricks as place holders in the borders and mark the location of the plate. DO NOT glue baseplates side by side, there is always a little empty space in between baseplates which gets covered once you build on it.