It's getting harder and harder to find ready made potting soil without additives for holding moisture, fertilizing etc. It's time to mix my own. I already know to add perlite to those needing extra drainage (plumeria, adenium etc) But tell me your basic outdoor potting soil mixture ingredients please.

I use Mel's Mix, from Square Foot Gardening.

1/3 Coconut Coir (instead of peat moss) (get it from a local hydroponic store or amazon.com)
1/3 Compost (usually an OMRI listed garden soil...like Kellogg's...from Home Depot)
1/3 Vermiculite (also from either local store or amazon.com)

Plus, I add azomite (amazon.com) and worm castings (amazon.com).

Thank you Adam @cadinkis. They have all that at my Home Depot!

Last year I bought bale of mix from a nursery- I think it's a good value that way and feels like money in the bank.
For some plants, I use a lot of fine bark mulch in the mix. I even had good results with a Sanseveria in straight bark.
Downside is, if the bark chips get dry, they take some effort to rehydrate. And I think I was leaving the baled mix too loose, not pressing it in quite enough, and some plants tended to be too dry.
I do recycle used mix into new outdoor pots.