depends in what....
pennies i have luck, so far this year i got some wheat's including a 1910. i have also found a 1983DD. in total witch is about a half a year i have found over 50 wheat's, and many error coins
nickels i haven't really tyred that much, but i have gotten many pre1960. and some errors
dimes i have gotten about 15 silvers 2 of them are merks.
quarters i did great the first $40 i ever got produced 1 silver and a 2004D extra leaf quarter, then after that i went back and got around $300 and got skunked.
i have not tyred halves yet but many people are doing good with them here
i have only gotten 4 Ike dollars, then a few or so later i sold them for $1.30 each.