They probably mean that the top half of the suit jacket has a canvas, which is a material that's used to give it structure and shape. The bottom half doesn't have the canvas. There are lots of makers that use this kind of construction. Sometimes to save on cost, sometimes for comfort. It's a fine construction technique.
My general take on this project: to be honest, it's probably a bad idea.
Custom tailoring is generally a risky endeavor, even when you're going to world class tailors. There are tons of things that can go wrong. Even if the tailor is perfect, maybe his idea of a good looking suit isn't the same as yours. Or maybe you choose the wrong fabric (sometimes it's hard to tell how something will look until it's made up. Maybe you choose the wrong details (e.g. going with flapped pockets instead of patch). Or maybe the tailor had a bad day and, even if he's normally good, this one commission just didn't turn out that well.
There are also lots of tailors that just aren't very good. It's hard enough picking a tailor when you know what you're doing and have tons of personal recommendations, have seen the garments in person, and feel like you have solid footing on what you want. Once you throw in the idea of wandering around some unknown country trying to find a tailor through the internet, it's usually a bad purchase.
That said, the suit above is fine, even if the general silhouette isn't personally to my liking. But if you wound up with something like that for a few hundred bucks, I'd consider it a success. The problem is that you'll probably have a big selection bias online. Lots of people may know they didn't get a good product and just don't end up posting at all.
Years ago, I was in China and commissioned some custom garments. They didn't turn out very good, but I also didn't pay very much and was expecting to chalk it up to experience anyway. The other problem is that, often, these cheaper tailoring shops don't use good fabrics. If they're charging you $150 for a suit, that wouldn't even cover the cost of good cloth (basic suit fabric from an English mill, for example, would run you about that much with shipping, even at wholesale prices).
My feeling is: unless your husband is a very unusual size (say 34" or 50" chest, above 6'3" or under 5'6"), you're probably better off the rack. SuitSupply has suits for about $500-ish, I believe. Spier & McKay is around that price mark. They are off-the-rack, which unlike custom, means you can try something on, judge how it looks, and return it if you don't like it. Custom tailors who allow you to return items should always be avoided because they're bad. Custom tailors that are good won't allow you to return items, but there's still a big risk.
If you're doing this just for fun and want the experience, by all means. But if you're doing this to get a good suit, I would recommend looking somewhere else.
That said, Vietnam is a great country and I'm sure you and your husband will have fun there either way. Which cities are you visiting?
Hi dieworkwear,
I'm not expecting SR quality but a good workmanship and it's also about the experience. They offer CTM at ~100 to 120USD and I thought to buy one or two fabrics in Germany or order them online, so I won't have the issue about the quality of the fabrics. But seems I have to think again about the project...
BTW: We'll visit Saigon, Da Nang, Hoi An and Hanoi maybe will make a trip to Halong Bay but not so shure about it...
Mary