Rifle rests can cost as little as $30 dollars to upwards of $500 depending on how much you shoot and what kind of accuracies you're looking for. For just sighting in, sand bags may suffice depending on how well you can hold a rifle. I do quite a bit of load development and use a rest made by Wichita that cost about $120 not including the front and rear leather rest which are sand filled. Try some shot shell bags (the older cloth ones filled with sand), tie them off with the electrical wire wraps. You would probably need about 5 of them. Stack two or three for the front rest and a couple for the rear. I get pretty good accuracy with my Harris bipod on a bench at the range, this may work for you also. I certainly don't get the .5" groups that I get with the Witchita but the sand bags or the Harris bi-pod should work fine for sighting inn.