I'll be in London for a week and a half next month and am contemplating cellphone options. Ordinarily I see losing phone coverage as a perk of vacation but this trip will be the first time in awhile I will need my phone and data. Verizon wants to charge me $10 a day which is absurd but may be necessary. What are UK sim cards like? Are they worth it? Any other suggestions or recommendations would be greatly appreciated. Thank you.