yeah growing in the long run will be way cheaper cause you only have to pay for the set up once and if you do it right you can have a rotating crop that could last your whole life
^^^ thats when you get untwanted attention. but yes, you may pay electric bills, but regardless you could have a steady supply of good bud for a monthly payment of slightly increased electric bill that would be much less then what you would pay for buying the amount of weed you grow.
well it really depends... if you only do one grow and lets say you start with 4 plants and 3 dont come out and only one does you prob wont get much bud out of it. If your planning on doing a couple of grows, obviously growing would be cheaper.