On trial accounts all searches, to the 100 search limit, are free.
On trial and live accounts, we also have some free postcodes you can test with (these do not count towards your 100 trial searches):
UK Postcode Lookup API – the free test postcodes are AA1 1AA, AA1 1AB, AA1 1AD and AA1 1AE. They represent fictitious data.
Auto-Complete API – you can test for free with our own real postcode SL6 1QZ. The data is real and has a mix of residential and commercial addresses.