I'm ashamed that I'm a cheap SOB. I use 9" white paper picnic plates, and use a black magic marker to make my bullseye, and I nail them up on a tree or if at gun range I'll staple them on the backboard. You can see them quite clearly as far off as 250yds, but at that distance you do need a spotting scope. What's good about them is if you don't get a bullseye is you'll see the dark background color, and if you don't see your shots, you know you hit whatever size circle you made for the bullseye. Cheap. Effective. and only around $3.00 for package of 50. You can also use other markers and be as effective if background would interfer with a black marker. If I need to zero a new scope, I don't use a marker, as I just stand off 10 yds to get an indication as to where I'm hitting then do a quick scope adjust(as long as it's a small adjustment) until on paper, then I put a circle on plate, or find out what's wrong with scope, or mount. If all's OK, I'll then measure off yardage that I want my rifle/pistol to shoot at for my distance to get that game animal.
Del