How to order a Trial SIM?

[RokeJulianLockh]

I use SMARTY, but they don't provide anything except whatever my AOSP-derived OS classifies as 3G (rather non-specific, considering the myriad implementations https://en.wikipedia.org/wiki/3G#Overview lists) where I live. Consequently, I want to try some other providers, notably O₂, but see no way to merely evaluate my ability to connect without paying.

[pgn · Accepted solution]

Cheapest way is to get an O2 PAYG SIM and pay £10 for a month's usage, @RokeJulianLockh - once your month is up, the SIM can be disposed of and you owe nothing more. Trial SIMs are not a thing these days. You can pick one up free in any O2 store or order free on-line https://www.o2.co.uk/shop/sim-cards/pay-as-you-go - first top up can be done using a voucher from same O2 shop or anywhere showing the PayPoint logo (newsagent, etc) Guide How to Top Up (PAYG) 

Good luck!

[RokeJulianLockh]

Actually, @pgn, that appears to be exactly the trial SIM I desired  — merely choosing a “bundle” doesn't actually force me to pay for it, so you've solved my problem.

[pgn]

You're welcome, @RokeJulianLockh 👍🏼