I currently have two 5K iMacs (one at home and one at work) and I shoot on a gh4 for both work and personal projects. I am looking for the best storage option for me for my home computer that will be fast enough to be able to edit 4K footage with this computer. I assume Thunderbolt is the best option for me with this computer?

For work I currently use this (https://eshop.macsales.com/shop/Thunderbolt/External-Drive/OWC/ThunderBay-4-RAID5) drive set up with RAID 5 and it works wonderfully. While I suppose I could go with the same setup at home, I really don't want to spend that much money.

Any suggestions?

I would be shocked if basically any USB3 drive wouldn't handle what you needed. I mean, not as well as one of those OWC RAIDs, but a straight 4K edit should be fine.

I use one of those toaster-looking things and swap bare SATA drives in and out.

These are your options in order of price/speed. Raid 0 for around $500 but a riskier solution if one of the drives fail it all fails.
1. Fast single drive.
2. SSD
3. Raid 0

This link
Hard-Drive Solutions for Video-Editing Studios | explora (http://www.bhphotovideo.com/explora/video/tips-and-solutions/hard-drive-solutions-video-editing-studios)

https://eshop.macsales.com/shop/Thunderbolt/External-Drive/OWC/ThunderBay-4-RAID5

Good choice.

If you can afford the mini with SSD drives you would have a very fast portable solution.

Not sure the kind of projects you work on, but I do commercial work with multiple tracks and need the fastest setup I can afford.

A big consideration is the codec that you shoot with and the number of layers that you composite. If the content is highly compressed and you use few layers, a simple SSD will do the trick. Use HDDs as backups. For compressed video, the bigger consideration is a fast CPU, lots of RAM and a good graphics card. The graphics card is especially important if your NLE can use its cores for encoding and decoding.

On the other hand, if you work with uncompressed video or lightly compressed video with lots of layers, then a good RAID is the way to go.

BTW, I recently read one person claim that she preferred editing 4K video on a 128GB iPad Pro(!) compared to her one year old iMac. I'm not sure what tools she was using, but I'd bet that she's editing highly compressed iPhone video. Don't try uncompressed video on an iPad!

So I currently have a 5K iMac with an i7 and 24gb RAM, I edit with Final Cut Pro X and shoot with a GH4 and in 4k. I guess I would prefer to have some redundancy, but I guess at this early stage of my career with not many videos happening personally, I wouldn't be opposed to getting something other than a RAID.

I've heard of people just buying SATA drives and getting a case for them and then using those to edit from. Do you think that makes sense for me?