Oscilloscope Bandwidth?

In all reality a 20MHz scope is good enough. Many will say that is wrong but 20 is all you need.
For total new engineering maybe a 30.

Since you're only interested in a digital scope and you have a tight budget, I'd consider the Rigol 1054Z 50MHz scope, then do a quick Google search for how to do the firmware "hack" to upgrade it to 100MHz. Probably one of the better bang vs. buck deals as far as new scopes go.

I prefer to do most of my RF work with an analog scope with a minimum of 100MHz bandwidth. I plan to upgrade to a refurbished 300-400MHz analog Tek scope as soon as money allows. I love my entry level (100MHz) digital scope for a lot of scenarios, but most of them in that price bracket have issues triggering on modulated RF envelopes, especially if there are a lot of harmonics present in the signal. With how cheap scopes are these days, I'd never recommend anything less than 100MHz. If you're working on a 28MHz transmitter, you'd never see 3rd order harmonic distortion with a 30MHz scope. Plus, many HF rigs use high-side injection with LOs much greater than 30MHz. Basically what I'm saying is, get the most bandwidth that you can afford. It's better to have more than you need, than less.

73s

I have a Siglent 2 channel, in 200 MHz.

https://www.google.com/search?q=sig.....69i57j0l7.4320j0j4&sourceid=chrome&ie=UTF-8

It may bust your budget, but may be worth looking into. I've used it for light duty, really, but it's been a good scope. It has features neither you or I can find useful now, but may leave some room for expansion.

People love Rigol, and they may have reason. I don't have experience with these brands, and think Siglent has been good from what I've read.

It all depends on what the person is doing with their gear. If it is for occasional alignments and monitoring your station an older el cheapo is great, but if you are opening a "Shop" I always tell them to buy the best they can afford without taking food off of the table.

I use 30MHz scope. Works as it should.