Hire purchase and shop credit are two different ways of paying for an item in instalments. Hire purchase is now generally used only for buying cars, and it differs from shop credit in that the car still belongs to the vendor until the instalments are fully paid.
As a rule of thumb, never buy anything on credit which has a value that won't outlast the payments.
Work out how much you will actually pay - including interest and any service charges.
Find out in advance what penalties the contract specifies in case you miss a payment. (It may be that the entire balance then becomes due.)
Beware of added features you don't really need or want, such as insurance to protect the loan.