Planting grass

I’m a renter and don’t know much about grass other than mowing and edging. Back yard is patchy and full of weeds. Had a lawn care guy out saying using weed and feed would just kill everything and recommending sod. When we moved in the yard was sparse already. I’m not looking to spend that much and improve what was there before. Wondering if I should just get a seed spreader and try to fill in the bare spots or if it would just be a waste of time and money. I bought several bags of cheap seeds last year and just threw them around without great result.