I'm also in Canada and I'm using Falim gum. I like it just as much or more than Mastic gum. I chew two pieces at once and save the chewed gum in the wrapper when I'm done with it for the day. I use the same two pieces for the whole week. It loses some of its hardness over time but it still works well to make my entire jaw sore when I chew it for long enough. Here's a link if you're interested. I get the plain mastic (100 pc) kind.

https://www.ebay.com/itm/TURKISH-CHEWING-GUM-FALIM-SUGAR-FREE-/152290269580

Amber, what you've linked to are actually just pills of mastic powder, meant to be taken as a medicine for digestive issues.

This is the gum form: https://www.amazon.com/Greece-Greek-Mastic-Mastiha-Mastixa/dp/B008RT5TRA

It's still not cheap, but it's the one everyone uses and a rite of passage for being involved with the ideas of this community. I suggest giving it a shot. Each piece can last for quite a while depending on how long you chew it and how you store it. Be aware that it is possible to overdo things with this gum and overwork yourself. If you find it too tough for you, it can be mixed with other gums. For instance you can break off a small piece of the mastic gum and chew it with a piece of regular gum to make the regular gum a bit more tough.

As Morphy said, Falim is another interesting gum to take a look at. I personally never enjoyed chewing it - I find it to be neither soft enough for long term chewing or hard enough for intense chewing. But give it a shot too since every body is different.

Go to Wal-mart and go to the ethnic section and buy this.

https://www.walmart.com/ip/Sharawi-Mastic-Chewing-Gum-100-count/55348292

This is the gum I've been chewing for a year. 2 bucks for about 100 pieces, add pieces as needed to adjust difficulty. For reference I've tried the mastic gum from Amazon and I feel no difference between that gum and this gum as far as toughness goes.

Ebay! Also it last a long time don't worry I'm still on the same pack I ordered like 2 months ago