Home Built Or Shop Bought?
Yes, it is better to buy your lenses and camera bodies from the shop rather than make your own out of wood. Artistry and skill only go so far when the material is white pine and the end result is a DSLR. We have seen a rather wonderful little wooden camera made by Leica but it is a toy rather than an working instrument.
Likewise, knitting your own memory cards is fun but the failure rate is high - better to buy San Disk or Hoodman at the outset and save the needles for socks and gloves.
The question gets a little closer when you consider accessories for a studio. A commercial light tent is still a good buy if you need to have a portable environment for product photography. You could make one yourself but you'd end up with a big monster that would not pack away when you need to change jobs. Ask me how I know, and where I store the damn thing.
Likewise, if you are going to sling expensive strobe lights in the studio, sling them on proper light stands and boom arms. Home-made wooden devices can work but with a great deal more bulk and a great deal less security. At the very least, use Manfrotto or Kupo spigots and hardware.
You can suit yourself if you want to use cardboard sheets for flags and reflectors in the studio - the material will eventually break down but it might be cheap enough to start with. Be kind to yourself if you intend to use a reflector at the beach or out on a job - get a commercial folding one ( Be really kind to yourself and get either a Profoto or a Lastolite.)
Lights? Go look at the bargain types available at Bunnings and imagine what it will be like working with two 1500watt workshop lights on yellow stands in your spare room in the middle of February...Suit yourself but don't expect to shoot ice cream or seafood shoots in any degree of comfort.
Is there anything you can make yourself? Yes - there are no end of specialist flags and shade boxes that you can make with matt board and gaffer tape that can be perfect for you. Get a Stanley knife and a steel straight edge and slice away. If some of your accessories have red, sticky fingerprints after this...well, you'll know better another time.
PS: you can indeed light your studio with Leyden jars or a kite and a key in a thunderstorm...or with no-name strobe kits bought off eBay. If you choose the low-powered versions they can just barely kill you...