Not too expensive, get a big botle of plain olive oil for $7.50, some lye, you can make 2 lbs of soap with it. EVOO is must for cooking but regular is higher acid so not a bad choice for soap. If you let it harden well the 10-12 bars will last over a week each, sometimes months if you care for them right.
I make soap with olive, coconut, hempseed or macedamia nut, and castor oil.
28oz olive
8oz coconut,
2oz hemp or macademia
2oz castor
12 to 15oz water (lower water and it sets up faster)
5.5oz lye
Measure the oils by weight, melt and stir together ideally in a double boiler but right on the stove low heat works. Measure water and put the container in a bath of icewater in the sink. Don rubber gloves, open a window, maybe put on and apron and safety goggles, and measure the lye. Add it to the water and stir. Take off safety gear, prepare your molds. Wait 15 minutes or so put gloves etc back on and check the temp on oil and lye/water, once both are 105 to 110F pour the lye/water in the oils and stick blend until it thickens, stir in any extras like .25 to 1oz essential oils, 2-3oz honey, or 2T of clay, then pour in the mold. Wait a day then unmold and finish as you like. Safe to use in 2 weeks, wait longer for a milder harder soap. The lather and cleansing is great on this and it leaves you feeling so soft and smooth.