I think I paid about $17 for my one gallon ones.

They grow very quickly. I've planted many from cuttings. You should be able to get from cutting size to 7' in just a few years, so it wouldn't be worth it to me...but it really depends on how much instant satisfaction is worth to you.

Planted smaller they do take several years before they go into production (establishment and all). So perhaps that's not too bad a price for something already bearing.

Price would really depend on where you live and ease of access to different varieties, plant sizes, etc. If you are in zone 8, your local Costco may even carry them.