For non-fragile items, I usually fold them and place them inside a poly mailer (to prevent water damage). I then put the poly mailer inside a plain brown manila envelope ($9.99 for a box of 100 in Staples). I've never had an issue using this method as items sent using light packet are handled as lettermail. If you're afraid that the envelope will get damaged, you can reinforce the sides with tape.
Personally, I don't use bubble mailers, because they're relatively expensive ($4.74/12 pcs in Staples or $0.44 per mailer after 12% tax). I usually buy poly mailers from China for about $0.08-$0.11 per mailer. It often takes a month or more to arrive though. If I need to send items on short notice, I usually just reuse the clear plastic clothes bags I get from shopping in stores or online. You can also use large ziploc bags if you can get them for a good price.
Also, bubble mailers tend to make the item thicker and if you're shipping something somewhat thick, you may not be able to ship the item as light packet/lettermail.
I recommend making your own mail slot template (some sellers refer to it as the "slot of doom") based on the maximum dimensions for oversize lettermail/light packet. Using a piece of cardboard from a large old box, I cut out rectangle (38x2 cm) with a cutter. I use this template to 'test' that my packages are within the 2 cm requirement. I've had one package returned to me prior to that because it was too thick and I had to ship it as a parcel. If you're a Venture One member, you can also buy a template online from Canada Post, but I don't recommend doing so as you can easily make one yourself. Just be careful when cutting the cardboard--my kitchen table has some light nicks due to my carelessness.
One reason why I prefer my method over bubble mailers is that items shipped this way tend to look like documents and not packages. I do ship them as light packet internationally and there's a customs declaration on the back, but I think a boring brown envelope looks less appealing to a potential thief. This is just my opinion though. I don't actually have any statistical basis for this, but I have had no INR cases so far. But I do block Africa, South America, most countries in Asia and countries like Italy, Brazil and Russia, so..
By the way, if you're shipping to Europe, some countries (Germany and Switzerland from my experience--even for inexpensive items) require two copies of a commercial invoice attached outside the package using a labelope/plastic envelope. If you're a Venture One member, you can get them for free from Canada Post. If you don't attach an invoice outside the package and customs doubts the declared value in the customs form, this may slow down processing. Customs may even withhold the item from the buyer until they present a commercial invoice. Most European countries don't require this if the item is not shipped using Xpresspost/EMS (I've shipped to the UK and Sweden with the invoice inside the package), but just to be safe, I think you should put an invoice outside.
Is the person a new buyer? Some buyers that live in EU-member countries and who often buy from sellers within the EU aren't aware of potential customs delays and that they may be charged VAT and/or duty if they're buying from a country outside the EU (e.g. Canada).
I usually wait two business days (as stated in my listing) before filing an unpaid item case.
