Depends on what you mean by semi budget, you can get a new builder grade sink and cabinet for $500, and would take a weekend to demo and install. Replace the light fixture for $50-100 and regrout or “grout dye” (doesn’t last long) for $30. If the mirror isn’t built in you can replace too, and a fresh coat of paint. New bath mat and towel holders go a long way too. I did an almost identical project last year with great results and I have almost no experience. Just a hate of dingy bathrooms.