Sugggestions for better type of fabric dye and how to reach the company from Canada?

I don't know a dye company in Quebec, but the good dyehouses are all mail-order anyway, and actually will save you quite a bit of money compared to the all-purpose dye sold in local shops, besides providing much more suitable dye. G&S Dye in Toronto is excellent. I recommend that you order your dye from them.

Do NOT use all-purpose dye such as Tintex Hot Dye or Rit. You would have to simmer the shirts in it for half an hour, or longer, for good results. I cannot imagine taking on the job of boiling 150 shirts! Use a "fiber reactive" dye, which can be used in cool water, and which also produces brighter, prettier, and more permanent results. Using the right dye is the most important part of dyeing, by far. G&S sells Procion MX dye, which is the favorite of dyers in North America and Europe.

The Starter Kit at http://www.gsdye.com/Canada/ProcionMX.html will dye up to 24 t-shirts, for about $30 Canadian. For 150 people, I would want to have at least nine ounces of dye. (One ounce is about 28 grams.) I recommend that you buy 100 grams each of 405 Hot Pink (actually a good magenta for mixing), 208 Bright Yellow, and 510 Turquoise (all other colors, except for the dark ones such as black, can be mixed from these three colors), plus (optionally) 50 grams of one of the blacks. Getting more dye than you think you'll need is not a bad idea, and if you have a favorite color among the pre-mixed colors G&S sells, you could go ahead and buy some of that, too. A little bit of black on a shirt makes the other colors look brighter.

You will also need urea, and soda ash (sodium carbonate), see http://www.gsdye.com/Canada/chemicals.html , and rubber gloves for everyone, which you can usually buy in a local pharmacy or hardware store, and plastic squeeze bottles with yorker caps (http://www.gsdye.com/Canada/accessories.html) to put the dye mixtures in, for squirting onto the tied, soda-ash-soaked shirts. You do NOT need any salt or sodium sulfate, as these are used only in immersion dyeing, not in tie-dye. Synthrapol or TNA Soap is better than other laundry detergents for washing out excess dye afterwards, but regular laundry detergent can be used. Don't forget vast quantities of rubber bands - smaller ones are best. Be sure that everyone wears old clothes while dyeing, as the dye will spatter and ruin good clothes.

Be sure to use only 100% cotton shirts. 80% cotton will work, but 50% cotton will produce pale colors. Use 50% cotton only if you want pastel colors.

You should try dyeing just a few shirts at home first for practice. Instructions are on my web site and others, and will also come with the dye. Color placement is a key point in how the results will look. Also see http://www.dharmatrading.com/info/groups.html .