There are definitely some good options for soaping oils in the supermarkets. Do a bit of searching and reading here on the forums and you will find good info on using shortening for a low cost oil. Read the ingredients like you are doing now and make sure you know which type to pick in whichever
soap calculator you are using.
I started out with the more expensive base oils like coconut oil and olive oil. After making soap for about a year I am becoming more cost conscious and experimenting with the cheaper base oils like shortening, lard, sunflower oil, soy oil, etc.
The more expensive oils may have better label appeal but I think you can make soap that's just as nice to use using more common oils. Plus, if you use cheaper oils for the main oils in the recipe, it's easier to afford luxury oils and butters that you use in smaller percentages.