If it works like Germany (not saying it does) local fare networks take precedence over the national rail prices. For instance, Deutsche Bahn can not sell you a train ticket on a regional train within a local fare network, like Bingen Stadtbahnhof to Frankfurt Hbf. That ticket can only be purchased from the RMV (Rhine-Main Transit Authority). You might travel on a Regionalbahn that originated outside the network, but inside the network, the locals get the ticket money, and it is the same whether it is a S-Bahn or a Regional Bahn, or a Regional Express.
So since a TER is a regional train, I'll posit that inside the Ile de France Network, fare is the same whether it is a TER or the "J" train. The network map shows rail lines outside as "tarification hors Ile-de-France". Until a "boots-on-the-ground" Parisien chimes in, I'd go with that.
PS I guess Tocard just did, but the www.oui.sncf site will not give a price either. Panguitch, Utah must be the 21st arrondissement.