This question already has an answer here:
I understand why reputation limits user actions, as it makes moderation easier, however it's very frustrating. I've got a few fairly niche GIS questions, and i'd love to be able to comment on older questions to speak to people who have had similar problems in the past (since messaging people directly isn't a thing here), but I require a certain amount of reputation to do so. Unfortunately, because I'm new to GIS, it's not as if I can answer any questions competently enough to gain that reputation.
Also, maybe this is better suited to a separate thread, but is there a way to purchase reputation to use for bounties?