Ballpark cost for septic system and well?

I understand there's a large number of variables, but does anyone have general info on the range of cost. I've never had to put in either and I'm thinking of buying some undeveloped land. Before I get serious about looking or spend time with well and septic co I need to know if I should be thinking the $5,000-$10,000 range $20,000? or what? Thanks