boric acid in GTA

I got mine at a local pharmacy. Was cheap. Specifically boric acid powder. Call a few.

Usually pharmacies don't carry it but they should have no problem ordering it for you if you request it. It is easily available from their supplier (just not popular enough for them to stock it on a regular basis). Some pharmacies may ask you to pay for the item upfront before ordering (to make sure you don't just place the order then never come back for it).

(Also note--and this was a few years ago so it may have changed--but in the past I found Shoppers Drug Mart was sometimes reluctant to order in special order items. But anyways no need to drive around, just pick up the phone and call a few in your vicinity, you should be able to easily find a pharmacy that will happily get it in for you. Do make sure you are talking directly to the pharmacy staff not front store staff as they have different ordering systems, the front store will not be able to access the inventory that the pharmacy has access to.)

I normally get my chemicals from Sigma Aldrich or VWR Canlab.

Got mine at a Walmart pharmacy