One of the main RuneScape gold conflicts for people regarding OSRS is the subscription based model. And while i agree it’s not the most amazing thing, a month is not a bad price for a game that gives me as much content as this.
The main difference you’ll notice with Old School free vs premium would have to be items, and locations. You can go far in OSRS with a free account, some skills, skilling methods, and locations most locations are not accessible by free players.
However, as far as account progression goes, all the available skills to you can still be leveled. The methods for training will not be as proficient as some methods discovered in the bounds of premium.
A lot of newer players make the mistake of upgrading to RS gold premium too early the players that DO upgrade to premium that is, obviously a lot of players remain free to play before their F2P skills are at a decent level.