I hate to be negative .... or maybe I secretly revel in it ...

If you don't even know if you want a bike at all .... just get a bike. Stop trying to get the "perfect" bike when you don't know if you will be riding roads, packed earth, soft earth, pea gravel, or your couch.

Buying used is great i you are pretty knowledgeable about bikes. If not it is pretty much a crapshoot.

First of all, to buy used, you have to figure that you might need to change the tires and replace the tubes, and maybe the cables. if you have to replace the cables you have to readjust the brakes and derailleurs. Can you do all that?

it isn't hard,. and if you have some tools (the right ones) you can do it by following YouTube videos. So figure $60-$80 for tires and tubes (bargain brands) and $25 for cables .... you do have all the tools, right? And a floor pump .... and it is good to have a spare tube and a mini-pump for roadside repair ....

Then of course you will need to fine-tune the bike to your size .... you an get a stem for $30 and spacers really cheap if you need them. So .... maybe $100 bucks on top of what you paid fr the bike.

Does the used bike need a new chain? Would you know? And you can judge how badly worn the cassette is ... and could swap in a new one if needed?

If you get really lucky you will find a bike that someone bought for $800 and rode three times and parked in the garage ..... but you had best be on Craigs List or whatever non-stop, and ready to go as soon as the right bike shows up.

Do you have a friend who rides?

I would suggest trying BikesDirect (Save up to 60% off BIKESHOP QUALITY GRAVEL BIKES, CROSS ADVENTURE BIKES AT FACTORY DIRECT PRICES from Bikesdirect.com) and look at stuff like "Cross/Gravel Bikes $299 and Up" and "Cross/Gravel Bikes $549 and Up" and see what's offered.

The bonus here is that you will get an almost fully assembled bike with all new components which you can put together with ease and ride pretty much right away (I still recommend watching a couple YouTube videos about adjusting brakes and derailleurs, because the cables will stretch after a while .... and if you are going to ride regularly, it will save you beaucoup bucks.) Alternatively you can go to a local shop and ask how much it would cost for assembly, and then buy some cheap accessories so they make a little money and see you as a possible repeat customer.

That way, if after a month or two, you find you don't like cycling, you can advertise it as "almost new, barely ridden" and probably make most of your money back .... losing nothing or at least a lot less that you would spend putting tubes and tires on a used bike.