I could help with that. As I have some experience in the fields of homemade cosplay. Both the cosplay itself and the props to go with it.
Regarding the actual cosplay outfit, it's always a combination of modifying a base design for actual sewing, and finding (and potentially modifying) some other clothes.
So, for the first part: 1. Find and define what the clothes of the character look like. Then go to a fabric shop, they will always have a large selection of patterns to choose from. Try and find the pattern that best matches the design, and make any necessary modifications from there.
2. When looking for clothes to modify or incorporate my best advice would be to go look at your nearest Salvation Army. That place is a goldmine.
When talking about props, the road can be very difficult, long, potentially expensive, and filled with hidden shortcuts and innovations.
1. From my experience, you're going to find yourself spending a lot of time in hardware stores. But my most prominent point of advice would be to never stop looking for things that could be part of something. It can be anything, a specific cut of pipe, a certain fitting whatever. This applies to everywhere else too. Not just the hardware store.
2. Never stop thinking about how to go about making something or putting it together. Something seem complicated? How can you tone it down into something manageable? Think outside the box and make something work, no matter how seemingly impossible.