I do my own nails: BIAB, colour, then top coat. Lasts about 3 weeks if I let it. Super easy to infill myself - I file off the top coat & colour, file back the BIAB, shape the free edge, prep the nail and apply fresh everything.
You apply BIAB just like a polish - if you can handle that, maybe you can try doing this yourself? I'd absolutely begrudge paying for BIAB/ gels these days.
My top tip to anyone who wants to stretch the time you make your nails last: ombre! I blend a colour from the free edge downwards, around a third of the nail, leaving the rest "nude" (just BIAB), then add a topcoat. You get all the joy of having your nails did with none of the obvious growth you get from a solid colour.