This is very tied into your prefed playstyle.
Collector is a pacifist role. You are designed to be roaming the lands.
Bountyhunter is a combat role. There are some bountys that dont have any combat in it at all, but for the moust part you will be shooting alot.
Both roles are exelent for a solo player. You do not need the bounty wagon cuz you do not need to do bountys that contains more then 1 target. If the bountyboard dont have any single target bountys, travel to the next one, it will have.
In terms of cash and gold bars, collector earns way, way more then what bountyhunter does BUT it requires time. I would say up to role lv 15 bountyhunter earns moregold and cash, from 15-20 collector leaves bountyhunter in the dust when your collection start to grows. (many of the items alone sells for 4-10 dollar per piece and completed sets sells from 100+-300+ dollars)
So, for a new player, your best bet is the bountyhunter first. Fokus on bringing the bountys in alive!!. You will get anywhere from 5-16 dollars per easy or medium bounty.
It is not mutch, i know, BUT it allows you to buy the early game stuff you need, like ammo, food and clothes.
Save all the gold you get AND do as many bounty related daily quests for more gold reward and use that gold to buy the collector role.
Play thru the online story missions. First time completion gives good cash and gold bonuses, enugh to kick start your rdr2 life aslong as you make the good decisions on what to spend it on. (like for bountyhunter, reinforced rope is a must have, but it costs 300 dollars......., and for collector the shovel and metal detector are must have but they together cost around 900 dollars..)
When it comes to weapons in order to save money there is ONLY 2 you need: schofield revolver and lancaster repeater. Why? cuz they both has high damage with defualt ammo and they both have very quick aim time. these 2 weapons alone can carry you true the entire time you play red2.