I have just renewed my annual contract for the telepeage machine ( £6.08) As we are doing France twice this Summer (1st time to Spain and Back and 2nd time to Beaune and back) it will be doing a lot of duty. We plan to do some of the driving on the local roads but when we do the longer legs it is a godsend at the booths as it can turn a 20/30 minute wait into a 10 second tootle in 2nd gear. If you are a regular visitor and do a lot of miles I can recommend them
https://www.saneftolling.co.uk/
The toll charges are the same as cash. There is a small set up charge and an annual fee. However the tolls are taken by direct debit so you are not handing over cash all the time and if you are driving solo you don't have to get out of the car at toll booths. My french friends also tell me that many car parks now use the same technology and that they work in those as well. I have not tried that yet.
Worst thing is that between the two trips we are in the UK for 4 days during which time my car has to have its MOT. This means that I shall have to remove the lens beam benders and then apply a new set for the 2nd trip!