You can use monthly income under a marriage extension, but it might be difficult for your initial visa and first extension. But from the 2nd extension it should be pretty smooth sailing if you've got a monthly deposit of at least 40k.
Monthly income for farang men need to be 40k or for marriage visa.
If the reason is marriage, AND you work with a work permit and make the minimum required income. Then you have a path towards citizenship. You can skip Permanent Residency too.