It's a fallacy that FOs cost more than EOs. I haven't found much difference in price between EOs and FOs, but I also favor the more modestly priced EOs. Most FOs seem to cost somewhere between 20-30 dollars per pound. Most citrus and mint EOs, and commonly used EOs like cedarwood, lavandin, eucalyptus, litsea, lemongrass, tea tree, anise, clove, cinnamon, rosemary, and clary sage are priced similarly to the average FO. Patchouli is higher (50-60 lb at a minimum) but you don't need much and it's a wonderful anchor for just about anything even if you don't like it straight. True lavender varies in price tremendously from the basic 40/42 up to Bulgarian and French varieties.
EOs like cardamom, ginger, and black pepper are more costly but are strong and best used as a small component of a blend so the overall cost of using them is reduced.
Of course if you use real chamomile, rose, jasmine, neroli or sandalwood EOs or absolutes, that's not cost effective.
For EOs that I can't afford or won't use for ethical reasons, I use an FO substitute. I like to blend and this works for me.