Simplicity offers a few different versions of the peasant blouse, and you're quite right -- they are very simple to make. Walking through Faires, I've always been taken aghast by the expense of some items that are really quite easy to sew. Skirts are probably the easiest of all, especially with an elasticised (albeit non-period) waist. Darts and buttons gets a little fussy.

Simplicity also has bodice patterns, but fitting those is always a chore. Sometimes, you can luck out, and the pattern just works for your body, other times, it just looks a little off. The best 'pattern' maker I've heard of for a well-fitted bodice is to take an old t-shirt and a roll of duct tape. Put on the t-shirt, and tape up your mid-section. Cut the shirt off with the tape shell, and section it. Those become the bodice panels.

For all the fuss they can be, it's often more worthwhile to buy -- the notions like solid brass grommets and the hefty fabric that's unlikely to pull apart... They're a professional sort of piece.

Be careful when shopping about though, especially if you go to some online stores -- bodices come in overbust AND underbust like the lovely one you're wearing in the photo. Don't buy one that goes up too high!