Unless your an expert money manager, stay away from maps with little money. These include almost all defualt maps.
Mod maps dont teach you about economy, at best you dont learn much, at worst you'll actually become a poorer player.
Maps like blood fued and dune patrol are good to start with (yr), as there isnt 'that' much to go around, the map is small and you have to manage relatively carefully. Also maps like heartland and cs are good, as they're kind of the same as the small maps but there's more to go around and stretch to.
Heck is next and obviously the 'cream of the crop' ^^ as you stretch for miles but all the time having to manage economy pretty perfectly due to most often being head to head with your opponent virtually constantly. A kind of tester map to show yourself how good you are at BO's and MC.
Power
Barrack
Ref
fac (1 minor or straight tanks)
ref (sell)
ref
is the standard BO for most maps to get the cash flowing, i think most people would agree.