I've just upgraded my EE sim only to this plan online:
12M SIM Max 30GB £41.99 £25.00
Monthly cost: £25.00
Although 30GB for £25 is not showing on the website for new customers, if they are prepared to offer it at this price as an upgrade without going via retentions then I reckon there's a good chance the call centre or an EE shop could match it for a new customer, but obviously no opportunity to earn cashback from quidco or topcashback.
Edit: Just noticed you already have an EE sim only, so check via my EE account whether it is eligible for upgrade and what plans are available. I had to scroll to the very right to find 30GB for £25.
Edited by CJ8 (Sun 23-Jul-17 12:34:13)