Bruge to Amsterdam train

Probably a lot of difference. The train from Paris to Belgium is a THALYS train to Brussels. That one costs more at the last minute than if purchased far in advance. The connection is to a Belgian train to Bruges that probably isn't different - I don't think it's a reserved train.

You can see for yourself. Go to the SNCF site and price out tickets for say tomorrow from Paris to Bruges.

Then price them out for a few weeks from today. (Tomorrow is Saturday, and Saturday tickets in a few weeks in summer high season may still be not that cheap - try a weekday a few weeks out.)

When I do this, I see that the one-way fare to Bruges is 115.80 euros last minute but a few weeks out it goes down to 59.80 euros, maybe even less the further out you go.

https://en.oui.sncf/en/

Or did you mean Bruges to Amsterdam (title of your thread) or Paris to Bruges (body of your thread)?

There is lower cost train option than Thalys from Paris to Brussels that I've used:
https://www.izy.com/en

Then you would just buy a ticket from Brussels to Bruge, at a fixed price one way about $20
https://www.belgiantrain.be/en

Haha! so sorry- yes train is from Bruge to Paris. I am also going from Amsterdam to Bruge, so unfortunately titled the thread wrong. Thank you for the feedback--I'll plan to get the tickets in advance if it saves that much money!

I would look at Jazz+Travels's response - that's a much cheaper train I wasn't aware of, and it might not save you as much to buy in advance vs. the Thalys train I suggested.

Thalys owns Izy sort of like SNCF TGV owns OUIGO in France; it just takes about 30 minutes longer than Thalys Brussels to Paris

clsygrl7, also note that advance tickets for premium trains are typically non-changeable and non-refundable. That means that you have to be certain to get to the train in time for your departure, or you lose all your money. When you look at the purchase website (which you should do immediately, even if you don't intend to purchase today), you are also likely to see that different times of day will have different prices - because of (typically) business-traveler demand. This is like air tickets. Think like you are buying air tickets.

You should also click on the link of a few listed trains to "expand" the actual routing. Most trains on your routes require at least one change. There's nothing hard about a train change, but you want to see where it is and how long you have to make the change. You'll be lugging your bags, and looking for an assigned (or likely, from Brussels to Bruges, an unassigned ... ) seat.

As other posters have said, If you purchase your ticket ahead, you will save a lot of money. We used Thalys from Amsterdam to Antwerp last year and then changed to Belgian Rail for the segment from Antwerp to Bruges with a stop in Ghent. We purchased the tickets on Thalys far enough in advance they were very reasonable and were able to spring for first class. You do have to make a reservation on Thalys; Belgian Rail, the tickets are open. We used the same website for all our transactions and our tickets were mailed to us in advance.
You can also take the IC (inter-city) train, it does not require reservations and the trip takes about 1 hour longer.
In short, the sooner you buy, the better the deal.
Have fun and enjoy!

If you're on a budget I second the recommendation for Izy, tickets are super cheap and the train is quite comfortable. Takes 2.5 hours instead of 1.5 hours via premium service Thalys, but it's still very quick.

As shown on the link, note that Izy only runs 1-2x/day.

Thank you, everyone! I truly appreciate your insight.