Is your target audience the tech / software industry? In my option, building an MVP with a few partners / co-founders shouldn't run you a long bill. Putting together something that just functionally works to validate the idea should not be very expensive especially if you have others to split the cost with. If building an MVP is turning out to be expensive for you - then you may be doing it wrong. Discuss more with your co-founders on what would be the bare minimum product to validate your idea (without any fluff) and get that going. Having worked with quite a few startups on their products and MVP - I see that some founders end up building a full product instead of MVP.
Besides building an MVP, I realize that you would have to bootstrap until you raise a seed / angel round of investment. I would suggest that if you have a day job, you may not want to quit until you have validated your idea with an MVP - that would give you a headstart. If you've already quit your day job and are working on your startup fulltime - use your skills, do some freelancing, help other startups / founders in ways you can - that should be good enough to keep you going.
PS: Of course, if you are not in the tech industry I can imagine building an MVP may cost more based on what domain your product is in.