I guess the biggest question here is what sort of coins do you like?
Roman, Hammered, Milled, modern .. any particular denomination (some find solace in sixpences, others Threepneces or Farthings or Pennies and all of their varieties.
Silver , gold or Bronze / Coppper, sets or presenation coins, piedforts, proofs or patterns - or maybe even tokens.
What can your budget afford based on the above?