You have probably caught up with the price of a brand new Alpacka raft (http://www.alpackaraft.com/alpacka-raft-series/) and put your canoeing dreams on hold, but there are cheaper options.
There is for example my home made pack raft (which costs less then A$40) that I posted about way back here: http://www.theultralighthiker.com/home-made-pack-raft/ for example. I have since thought that it would be better to attach the reinforcing bottom with a circle of tarp clips (such as these: http://www.theultralighthiker.com/easyklip/) connected together with a thin rope. It can be easily taken off to dry and put back on again before you re-inflate. And it is easy to replace if it wears out.
I have also mentioned Klymit’s much cheaper rafts (from around US$100: eg here: http://www.theultralighthiker.com/klymit-packraft/ & here: http://www.theultralighthiker.com/the-best-laid-schemes/
Now there is an even better option: http://www.diypackraft.com/shop/ What a resource this is! These folk offer a DIY kit from US$125! This is a very good price for a real packraft able to canoe serious white water! Their rafts start with an ultralight version at 815 grams!
Their page comes with every bit of useful advice you could possibly want. The site is positively encyclopedic. Their DIY seat plan is handy. Even their blog http://www.diypackraft.com/blog/ is impressive. It even includes a DIY paddle! Check them out.
I may start with their fabric sample kit (US$5.99 – free international shipping) and their http://www.diypackraft.com/2016/07/09/diy-heat-sealing-iron/ (I have some other projects in mind for heat sealable fabrics).
Their fabric prices are quite good. I compared them with a couple of other suppliers such as Quest: http://www.questoutfitters.com/Coated_2.htm#HEAT%20SEALABLE and Seattle: http://www.seattlefabrics.com/nylons.html Of course you can get them cheaper if you buy in bulk, eg Rockywoods: http://www.rockywoods.com/Fabrics-Kits/Heat-Sealable-Nylon-Fabrics
You will still need a paddle: http://www.theultralighthiker.com/ultralight-paddle/
PS: I have the Fiord Explorer pack raft from Alpacka, what they call their ‘Moose Boat’, because you can pack a whole moose carcass in it. You need to consider just how much you might carry before you purchase or make your first/next pack raft.