Congratulations on your baby on the way!
I know about 5 healthy babies raised on homemade goat’s-milk-based formulas when the mother was unable to breastfeed. The moms followed very specific recipes that included things like flax seed oil. I think it can be a legitimate and healthy choice…no formula is going to perfectly replicate breastmilk and you have to find one that your baby tolerates and you are comfortable with. I think the Weston A. Price Foundation offers formula recipes that have been used by many and aim to have the same caloric content etc. as breastmilk. Having not used them myself I’m not going to endorse any particular recipe.
I don’t know that homemade formula is going to be cheaper, most people I know do it because it doesn’t have the corn syrup, GMOs, soy, etc. that commercial formula does.
I know that feeding your baby is an important and personal choice and that you asked about formula. I’m just going to throw these two options out there as well since many people aren’t aware of them, I hope they do not offend:
Donated breastmilk: I’ve donated to several adopted babies and one whose mother couldn’t nurse due to cancer…I gave them a copy of my prenatal blood labs to confirm that I was free of diseases…you can find donors through organizations like Human Milk for Human Babies. You can also sometimes purchase breastmilk from a milk bank, but it is very expensive and mostly goes to premature or sick babies.
Adoptive nursing: It’s also possible to lactate for an adopted baby (I’ve heard it’s easier if you have lactated before but it’s not necessary). You would want to work with a lactation consultant and/or get support from La Leche League leaders or something to that effect. Many adoptive nursing moms supplement with formula (either on bottles or at the breast with a supplemental nursing system) but are able to give their babies some breastmilk. Every drop helps!
Blessings to you and I hope you can find something that works well for your baby, whatever that is. Sometimes babies’ digestive systems have their own opinions about things!