You don't need expensive supplements, organic produce, or a fully equipped home gym to build muscle. The fundamentals of muscle building are simple, and most of them are free or very cheap.
Protein: The Most Important (and Affordable) Nutrient
The best budget-friendly protein sources: eggs (about 6g per egg), canned tuna and sardines, chicken thighs (cheaper than breast, more flavorful), beans and lentils (high protein and fiber), Greek yogurt (protein-dense, versatile), cottage cheese (casein-rich). You do not need whey protein to build muscle — whole food protein is equally effective.
Budget Training Equipment
A basic home gym doesn't need to cost thousands. The essentials: a barbell and plates (or adjustable dumbbells), a pull-up bar, a bench. Many effective programs have been built with just a barbell and some plates. Bodyweight exercises — push-ups, dips, pistol squats, planks — are remarkably effective when performed well.
Programming on a Budget
A 3-day full-body program using compound movements — squat, bench press, row, overhead press, deadlift — covers every major muscle group efficiently. Train three times per week. Add weight or reps every session. Eat adequate protein. Sleep well.