Ours was 10K $ can (about $8k us) and was professionally done. If you can do it yourself and you think you are doing a good job go for it. These prof builders are sometimes more talk and with the last deck builder did not do the final inspection. It seemed like a small point but it was a big point that I overlooked.
After the deck was built the builder went bankrupt and the city building inspector came out and told me what needed to be fixed. It was mainly to do with the stairs. I took about a month to fix it up and the inspector gave it my approval.
Yes as mentioned above planning is important but if the deck is low lying and has minimal stairs then there should be less issues. Check the local building codes to make sure you are conforming. Deck looks good!
