You need a good quality 5w30 fully synthetic that meets SN spec. There are loads out there at reasonable prices. Asda do a couple that meet that spec for £15 for 5 litres. Paying more will not make the oil better, it just means the company selling it makes more profit. Been using Asda brand oils for years with no issues and remember, Asda do not make oil, it made by a major manufacturer (used to be Millers) and simply rebranded.
Putting a value correct spec oil in will do no harm, using a very expensive oil in that does not meet the specs will a;msot certainly do long term harm.