Depends on the AT, power sets, and build objectives (cap defense, max recharge, max HP/end, etc.). For example, if you pay 5M each for 5 Luck of the Gambler +Global Recharge, that's 25M for only 5 IOs. Being PvP IOs, the Panacea and Gladiator's Armor proc IOs can cost 5-10M each, for another 10-20M. Purples can run that high as well, depending on the set, so 6 of those can be 30-60M. Add those up, and you're well into the 100M+ range.
But not everybody builds that way for every AT/powerset combo. I've built out chars for less than 50M, and a few for over 250M. It's hard to determine a general average that applies across the board.