This could end up being a long post but I hope you will find it worthwhile.
First, you need to determine what kind of light you want to produce. The best site to learn your options is
Strobist.
Since I wanted to use flashes instead of strobes, I wanted something that would have less spill than a shoot through umbrella. This site has some great examples comparing shoot throughs and softboxes -->
Umbrella vs. Softbox: a quick comparison | Portrait & Family Photography - Jacob Vorpahl.
However, softboxes can be kind of pricey so I found a reflective umbrella softbox that works great for my needs. Here is an article I wrote that shows the umbrellas I bought and the DIY bracket I made to hold my flash units -->
https://www.pentaxforums.com/forums/do-yourself/106596-diy-horizontal-flash-b...ht-stands.html. If you want more info on the equipment I bought and the costs, send me a PM.
Last but not least, once you decide what kind of lights you want, the Strobist Flikr forum was a great place to search for info on the various brands of radio triggers, light stands, ect. Here is their link -->
Flickr: Strobist.com discussion topics
Good luck with your quest for better light.
Tim