I would only use the information given by SNCF on their TER Normandy website, so: only for certain trains from/to Paris, only if you really have Paris as origin or destination and only on Fri/Satur/Sunday. That means you don't need a reservation on 23 June. You would need one on Sunday but you could make a reservation on the Thursday. Sunday morning is not likely to be very busy and I've also read reports that the ticket inspectors are not interested in the reservations.

Price should be a few euros, in any case less than 10.

The 10/20 are for the ´superfast´ hi-speed TGV trains-and seats on overnight.

For THESE NoMad trains the need to REServe-later simplified to only on busy days and to/fro P (where most people go to anyway) are now run as local/regional by the region Normandie=hence that name. IN the station in P are now gates that you can only pass with a barcode you get with the REServ.

Its best to ask at counter-preferably a day or 2 before when you are in FR anyway

Note that SNCF also offers in main season extra daytours (with bus+entry) to the carpets of Bayeux and the Mt St Michel-bringing you close by with these trains. You may be interested in buying these as supplmt to ease going there.

IF you have a pass with passdays it may very well be that such a special all-in ticket works out cheaper as using passdays

Thank you for your replies.  I will be arriving in Paris the same day that I need a train to Normandy so I wont be able to go to a ticket counter until the day I need the train.  Do these trains ever sell out or do you think I should be okay to get a reservation at SNCF counter in station on day of departure?

You said you were travelling to Normandy on 23 June, so you don't need a reservation on that day, according to the TER Normandy website. But on that day, you can already make a reservation for your journey back to Paris on Sunday morning.

I don't really know how busy these trains are but Thursday and Sunday morning should generally be fine.

Since there is no requirement to make a reservation on Monday-Thursday, there have to be other means to pass these gates.

Hello,

I have the same problem. I want to travel from Paris to Cherbourg on the 19th of May with the NOMAD train and I also get the notification “prices unavailable. It is possible that all passholder seats are sold out.”.

Through another community tab and differents websites (SNCF, TER Normandie...) I only got more confused. A friend of mine who lives in Paris contacted an operator there. As soon as I know more, I´ll post it here.

I too got the “prices unavailable. It is possible that all passholder seats are sold out.”, and the other available trains that didn’t need a reservation did not offer an e-ticket. I did not want to chance unavailability at the station 3 months from now, so… 
 
I checked the regular SNCF site as though buying a ticket, and discovered that although several trains were available on my travel day, only a few seats were still available (and I’m looking 3 months in advance), so I chose to purchase my ticket… and it seems it was a good thing, because several hours later most trains on my travel day were no longer offered (presumably all seats gone). 
 
So… 
(1) Eurail needs to address getting a printable ticket for the portion of an otherwise reserved voyage (e.g. Lille to Caen… Lille to Paris had e-ticket but Paris to Caen had none offered). 

(2) Eurail needs to provide real time, real person help/chat option instead of the substandard automated thingy.

19 May was a Thursday. No reservation needed.

The NOMAD reservations for Krono+ et Krono trains are only available in France from a ticket office or ticket machine. They cost €1.50 but are only mandatory in certain cases:

• Only on Friday, Saturday and Sunday
• Only on the lines Paris - Caen - Cherbourg, Paris - Trouville/Deauville and Paris - Argentan - Granville
• Only if you travel from/to Paris

The data SNCF send to the European Timetable Centre however says that reservations are mandatory for many more Krono+ and Krono trains, also if you don't travel from/to Paris or if you travel on other days. That is therefore incorrect. The rail planner app and reservation get their timetables from the ETC so they will show this incorrect information.

SNCF however are unwilling to make their information consistent.

This has changed and the Nomad Krono reservations are always mandatory but the Eurail site cannot sell them. The trains are almost never full. You can only buy them at Paris Saint Lazare and in Normandy and they cost only 1,50€ (hint: use “other discounts” to find them at the Nomad machine). If you can’t get one, explain the Problem to the train staff, they understand. Maybe 0,0001% of travellers use Eurail so the 1,50€ lost are not a big deal to the staff I asked. The Nomad Krono / Eurail system is currently broken and hopefully will improve.

I'm quite sure you can buy the reservation at any SNCF ticket machine. I was able to get one in Annemasse 3 days ago.