Sorry about the confusion. As far as I know the signals that I am trying to measure are 3.5Mhz and below but I was under the impression that just like a scope you need 10 times the sample rate to get a good signal. If I do not then what level of over sampleing do I need if any? Is it possible to connect 2 or 3 of the cheap ~$10 8 channel USB logic analyzers to the same computer and have the software use them as a single 16 or 24 channel logic analyzer? I have also looked at the 32 channel OLS logic analyzer for $50 but I am not sure that the software will do what I want (convert the data to hex) and looks complicated to setup. I will look at the more expensive scope as well.
Observing a signal to determine the fidelity of it is one thing. This is where you look at the shape of the signal, things like overshoot, ringing, glitches.. etc. Yes for that you need a scope with a much higher frequency than the signal observed, because the signal itself has higher frequency components in it you want to see.
But if you trust that the signal is good, and you just want the data that signal is carrying, the individual 1s and 0s. This is what an Logic Analyser does. Then no you don't need to oversample by a lot. Usually the specsheet of the logic analyser lists the max frequency of the signal it can handle and you should be good if the signal you're analysing doesn't exceed that.
I don't know about other USB based logic analysers out there. I've only used the Saleae (well and bitscope), which has very decent software, the reason why it's popular. And it just so happens that you can get cheap clones compatible with their software for peanuts.
I don't think you can hook up multiple LAs to it to form a one big one. But you could probably cheat with a VM and have two different copies running with USB bypass in order to use multiple units. If you trigger them both off the same signal, you should be able to observe the result in the same time period. It just won't be as convenient.