Quantity   Component name
4 × 18650 LiPo batteries .. or more, depending on your needs. Cost - nill
4 × 18650 battery holders. Search ebay for Single Slot 18650 Mobile Battery Clip Case Holder with Wire Leads Expect to pay about £1.50 for a pack of 5
1 × Micro USB LiPo Charger board. Search ebay for Micro USB1A 5V Lithium Battery Charging Board Charger Module 18650+Protection ET - expect to pay about £0.90p
1 × Roll of electrical tape I'll leave the choice of colour up to you.
1 × Micro USB USB Wall wart charger.
1 × Suitable connector to plug in to the dummy battery on the Canon camera. You can probably recover this from an old wall wart.
1 × Poly Fuse (resettable fuse) 2.6A (or thereabouts) ebay search "10PCS-50PCS Polyswitch SMT SMD Resettable Fuses 1812 2.6A" expect to pay about 20pence/cents for these.Less in bulk.
1 × Thermal protection - optional depending on your application Something like this perhaps. http://www.uchiya.co.jp/OtherContet/SeihinPageBPD_englishHTML.html