I’ve just signed up for the Bip & Go tag. I paid 24€ for the tag deposit ( extra 4€ for Italy). I decided on the Bip &Go because it covers France, Spain, Portugal and Italy, whereas some of the others (eg e-movis) you have to buy separate tag for France and Spain/Portugal.
It took me a while to sort out the direct debit as HSBC don’t do SEPA direct debits. I ended up opening a Wise bank account which you can use anywhere in the world and swap currencies. I transferred some pounds, switched to euros and it went straight through on the Bip &Go website. Plus we now have a euro bank card for the time we are in Europe.
The ‘ala carte’ subscription means you only pay €1.90 each month you use the tag, plus the actual toll fee by direct debit. This means there should be no queuing at tolls, hopefully. We are going Plymouth Roscoff then down to Quimper to start our few weeks over there.
Good luck if you decide to go for a tag.