Depends on the budget you have set aside. With any suspension height change, you'll want to replace the shocks with longer ones than the stockers, so factor another $150-$300 into your budget, depending on which shocks you want.
The poly spacers go between the spring and the body, and are the least expensive way to go. They will set you up with around 2" or so worth of lift over what you CURRENTLY have. If your coil springs have sagged a bit, which they do over the years, you'll not get 2-full inches greater than stock, you'll get 2-full inches greater than you have right now, which might be as much as 1" less than stock height, depending on how much your springs have sagged.
If you have more than 80k on the Jeep, you may want to consider getting replacement coils, rather than the poly spacers. They run a bit more both in cost and in shipping, but, they will give you a true amount of lift versus the factory ride-height.
Let me know if you have any add'l questions.
Thanks,
KevinF