Yellow chips are cheap, around $5-10 each. I bought a box about five years ago and still have a bunch left. I believe about 5-6 boxes were sold. You can still occasionally find the $5 chips, but they are not as easily found. $25 green are really tough. I estimate them as follows:

$1 chips: $10
$5 chips: $20
$25 chips: $30

I have not found one table to be easier than the other. They seem to be equally "rare."

I mentioned having "heard" of a $100 chip. I was told it was black but never received anymore details (like if it came in the two table designations as well.)