PLUS that all the fast TGV (the pride of state-run burocratic France) needs to RES-and this, together with cost of passday, may even cost more as a cheapish advance ticket.
TER-Occitanie offer very cheap weekend tickets in september, mostly only 1€, but thats TER only.
IF you really want to take such long and expensive returns so often, go in line for counter of the state-run burocratic SNCF and have them find something that may suit you. I however have the feeling that renting a room in Bcn will work out cheaper.
You can only travel in France on 2 of your travel days and only if you have a global pass. If you have a Spain pass you can only travel within Spain.
With the pass I can not return to France?
I would like a pass that allows me to do 3 or 4 round trips Montpellier-Barcelona
There is no such Interrail pass.
With a global pass you can travel on a maximum of two travel days in your home country.
With a One Country pass, which you can't buy for your own country, you have no travel days in your home country.
With the 10 day two month global pass can I make 8 round trips Montpellier (France) Barcelona?
With the 10 day two month global pass can I make 8 round trips Montpellier (France) Barcelona?
No. You can NEVER travel on more than 2 travel days in your home country (France), no matter if you have a 4 day global flexible pass or a 3 month global continuous pass.