+1 on the scope is probably the wrong tool. decoding OBD is best done with other tools, also because you have to filter group and decode the data from the decoded can packet.
you can do it by hand but it is a very tedious and frustrating task. been there. Still, i encourage you to do so at some point if you plan to really learn and understand what the hell is going on when you throw a glance at a can bus, i was doing that while studying the related iso/sae literature and trying to figure out if understood what i was reading.
If you plan to develop hardware a scope is of course essential because the shape of the waveform matters a lot. you will have some requirements in bandwidth, risetime AND FUNCTIONALITY. even though scope X has enough BW it may lack other stuff like the ability to work with eye dyagrams masks (or some workaround to do so) and naturally protocol decoding, with can being one of the most popular.
Correct probes are maybe not necessary but very important too.
then at another point you will want to try your circuit in a car, as said having a scope with isolated ground is preferable. isolated channels would be cake but a tek tps is the cheapest you can have.. and it's not cheap. also it is very very very limited. This is when usb scopes come into play.
Like a picoscope (though possibly not the lowest end model). I suggest you don't get anything else as an usb scope, because of the functionality.
You can do automotive work with it (i do, at least.) without paying as much as they ask for a lecroy ws3k plus the required options.. or a keysight mso3kt plus the required options.
bandwidth? check.
memory? check.
then in the software (valid for all models)
eye dyagram + masks? check (or with workarounds)
can decoding? check.
lin decoding? check.
uwire, sent, flexray? check.
the possibility to acquire hundreds of MB of waveforms and having it all decoded and ready in a table? check.
but, but, but... again, all of this is unnecessary and useless if you don't pland to develop hardware. first things first, and obd scanner and decoder.