What price do you get if you buy into a mutual fund on the ex-dividend date?

If you buy into a vanguard mutual fund before closing time, you get the close price at the end of that day.

But how is your price effected if you buy on the ex dividend date?

For example if the close price is $100 but the dividend is $2 would you pay $98 a share or would you pay the full $100, not receive the dividend, and effectively be penalized the $2 when the shares dropped after the dividend?