Around here most people put in 6" to 12" of "Class 5" gravel. It has a
mix of large and small rocks, sand, and some clay. Used as an
underlayment for all the roads so it's readily available. You can also
get a Class 5 made from ground up concrete, it will pack down VERY hard.
All of these need to have a fairly high moisture content then tamped
with a plate tamper. rent the tamper for $30 at your local rental place.

wrote:
I am the one asking about leveling the lot and wanting to "box in" with
2x6's with gravel and park on it for awhile till I can afford to build
everything. Is it ok to ly black plastic down before putting the rock
down to keep weeds, etc, from growing through?

Also, what size rick should I use. I plan on getting it myself and
shoveling by hand. I want something that is easy to rake etc, to make
level but will last too and not be too expensive.