Good video about Sigrok, and LA in general, Saleae clones, etc
DSLogic Plus review and teardown
You can compare the LAs supported by Sigrok, they are listed here:
https://sigrok.org/wiki/Supported_hardware#Logic_analyzersClick on the different LAs supported, you'll get into Sigrok's device page. At the right side of that page, you'll find a "resume" of the device, where you can see what it has, and usually a link to that model website /vendor website, so you can also get an idea about the price. Then look for better prices on ebay, ali, banggood, etc. I did that a couple of months ago.
Note that, the more channels used simultaneously, the lower sample rates from the LA. So look for the sample rate you'll get with the four channels needed for SPI. You'll need to have more samplerate on the LA than bandwidth has the signal on the DUT. The more, the better. At least twice. Also note that some LAs can work only in stream mode, which has sample rate limited by USB speed but has "infinite" memory, while others can also work in buffer mode at much greater sample rates, but with limited memory. In buffer mode, it's good to have compression so you can get bigger captures.
I think you can't go wrong buying a DSLogic Plus *clone* from Aliexpress or Banggood. It has buffer, bandwidth, memory, compression, triggers and state, that you usually don't get with the Saleae clones, yet it's quite cheap. I think it's the best bang for the buck. It works best with DSView, though, not Sigrok.
DSView downloads
https://www.dreamsourcelab.com/download/Many people buy the DSLogic Basic, then hack it via soldering memory. But the Basic's pod has DuPont-style cables that are worse as frequency increases. Price of the "good" pod makes more or less the difference in price from Basic to Plus, so I didn't think it was worth the hassle and got the Plus. Pick your poison.
I got mine from Aliexpress, 75€.
https://es.aliexpress.com/item/32970230062.htmlPlease note this listing shows a picture of the Basic model, not the Plus. I didn't have any problems, but perhaps you should contact the seller before buying.
Perhaps is a little bit too late to buy it now and have it before July, 1st comes, then you'll have to pay VAT and carrier fees, etc. As an alternative, you can get it on banggood shipped from CZ, but of course it's not so cheap:
https://www.banggood.com/DSLogic-Plus-Logic-Analyzer-5-Times-Saleae16-Bandwidth-Up-To-400M-Sampling-p-1284501.html