It varies by listing. Some shells include exterior siding, roof, windows, and doors only. Others add insulation, sheathing, or a rough-in for utilities. Read each listing carefully before you visit.
The upfront price is usually lower, but you still need budget for interior finish, appliances, permits, and labor if you hire trades. Factor total project cost, not just the shell price.
Financing options depend on the lender and whether the shell is on wheels or real property. Many buyers pay cash or use personal loans. Ask the seller if they offer payment plans.