Like any other loan, a bridging facility comes with interest charges and the loan amount is determined by various conditions, such as the valuation of the property you are seeking to buy. However, this are meant to be a temporary stop-gap measure and therefore tend to be more short-term than a typical home mortgage, which can span anywhere from 10-30 years.
You may also repay the bridging loan together with the interest in full at the end of the agreed term, instead of through monthly instalments that are typical of repayment plans for regular loans.