Buying feeders - how many, how often

Newbie here! We're getting a 4 month old beardie for Christmas, and while I've had iguanas before, this is the first time I'll have to feed someone live food. I've read up on what to feed him and will be starting with crickets from a local pet shop and likely ordering worms online as there aren't a ton of local sources. What I can't seem to find an answer to is how long feeders last so I can figure out how many I should buy at a time and how often should I plan to be buying/ordering them - i.e. how often should I plan to be stopping in at the pet store to buy crickets, or how often should I be putting an online order in for bsfl, hornworms, etc.?

One other question: We're in Victoria, BC, Canada - I know The Worm Lady and Supercricket are Canadian suppliers, but being on the west coast shipping from them (especially due to the cold of their winters) is really expensive. Does anyone know of any BC suppliers, or possibly even west coast American ones that would ship to BC?

It really depends on the feeders. At 4 months old your dragon will still eat quite a bit so I suggest offering as much variety as you can get. When I used crickets I went through about 1,000 a month (including dieoffs) I switched to a roach colony after that but you can't do that in Canada unfortunately. Black soldier fly larvae will last for a while in their substrate. I usually get a month or so out of a bin of 500 for my adult. Your younger dragon will likely go through them faster. Silkworms are nice when you can get them. You could get some eggs and try hatching them or just get a batch of 25 or so and use them as a treat. I'm not sure about suppliers other than the ones you've listed already but there are some others on here from BC who may have some input on that for you.