Hi I've sadly left things late and now face more expensive train tickets (Paris to London Eurostar)
The prices are varying widely - from $300 for 1 adult and 2 kids one way to $450 and up!
I will bite the bullet and pay the $300 but now when I go online there is a $23 shipping charge to send the tickets. Is that reasonable? Sounds like a lot to me but maybe I"m quibbling. We are in Canada and going through RailEurope.ca. The official Eurostar.com is much more expensive.
Any other possibilities? Should I just buy now before they go up again?
Our travel day is July 13th one way Paris to London
thanks!

I will go and play on the site for you. First, it is often chepare to book a return ticket not a one way. Second, why have ticket shipped, absolutely no need. Just print off booking confirmation and pick up ticket at station. I did and it worked just fine. Paying to have tickets delivered it silly and it one more thing to worry about arriving on time etc.

For 13 July the best price I found as of a moment ago at eurostar.com for one adult and two kids ages 4-11 is $340 US.

Yes, what a shame you didn't book earlier, oh well you only live once. And the Train is great with kids, city center to city center and the kids will enjoy the journey as at least they can walk around a wee bit.
You can save 23 dollars though by ordering online and picking up tickets at station!!

thanks for trying guys that was very kind!
I have just bought the tickets online. My friend in the Netherlands tried from there and got a quote of 400 Euros! So I'm getting a real bargain at $300 Canadian. Ha! It still beats schlepping to Charles de Gaulle and dealing with all the airport hassle.
Now to book Thalys tix for Amsterdam to Paris. That seems to be a lot more straightforward except that the screen keeps coming up in Dutch...which weirdly I seem to get the gist of. But, I think I will just get my friend to get them for me.