If an employer wants you badly enough to move you, most will cover the cost of a moving company, temporary housing for thirty to sixty days and one or two house-hunting trips. Larger companies may also buy your house if it does not sell within ninety days.
Ask for the relocation policy in writing before you accept. Find out whether the package is a lump sum or reimbursed expenses, and whether you must repay it if you leave within a year.