1. 2x4 are not 2" x 4" and when you start, you make a lot of assumptions that land you in hot water.
2. A beginner will not know what does "green" vs. "klin" mean and will have a hard time getting anything to be straight.
3. Construction lumber is made for construction and not interior use because of many different factors.
I would highly recommend choosing poplar 1x8 boards (they will neither be perfectly 1 inch in thickness nor 8 inches in width but close). They are easy to work with because poplar is soft, even though it called a "hardwood". And the wood takes paint and stain very well.
Also, with poplar, your list of beginner tools will be spot on. You wouldn't even need much more and I'm confident that I can put together a good enough kit for under $250 by using only corded tools and an extension cord.