Need cellphone advice (and your fave tourist spots) London

[Leah613]

Hi we are going on a much awaited trip for 6 days to my old town london. Whats best (cheapest) way of having cell calling access when not in wifi. Verizon offered a plan if we use it one time we get $10 fee for 24 hours per phone for calls etc. Just adds up. If not being used it has to be in airplane mode not to be charged. Theres gotta be a better way.  Also any of ur fave tourist spots? We only have 2 full days to tour. Thanks in advance

[Definitions]

When I went to London a few years ago I ordered a giffgaff sim from someone on eBay. The seller offered to top up the account for me because I think you need a UK Credit card.

The £8 or £10 plan should be fine. Use the bonus £5 credit for international calls.

You have to have a compatible phone and enough time for the sim to come