I have built up my "strobist" kit over several years and while I use the Olympus FL-50Rs in Bowens Softboxes and Brollies, I also use lots of DiY light modifiers and reflectors.
I also have lots of old flash guns (£5 off eBay) and slave triggers that I can use in all sorts of ways (including housed in sealed food containers in underwater/wet shots)
I simply will not pay out good money for a bit of plastic that I can do the same thing with a bit of black card and masking tape.
My shoot through white brollies have DiY silver reflector attachments made from the "Life" blankets that are used in emergency and sports events. They also make great wall/floor reflectors. The 5-in-1 round reflector with a translucent inside screen are excellent value and do a lot of things (including a kneeling mat)
There is a guy selling something called "black foamie thing" for many times what I paid for my one in the 99p shop
I have cut up plastic milk bottles and stuck cooking foil in them to work as background illumination reflectors. Coloured metalised Christmas wrap works great for introducing all sorts of "effects".
A valued bit of "studio" kit is a hairdressers block, which I use to work out different lighting arrangements.
Look forward to seeing some of your pictures.