The amount of traffic consumed when using a browser to access Reddit through proxies will vary depending on a number of factors, including:
The number of subreddits you visit
The number of posts and comments you view
The size of the images and videos you view
The frequency with which you refresh the page
As a general estimate, you can expect to consume around 1-2 MB of traffic per hour of browsing Reddit. This includes the traffic required to load the Reddit homepage, subreddits, posts, comments, and any images or videos.
If you are only using proxies to bypass bans on specific subreddits, you may consume less traffic, as you will not be browsing the entire site. However, if you are actively participating in discussions and viewing a lot of content, your traffic consumption will be higher.
To give you a more accurate estimate, I would recommend monitoring your traffic usage while browsing Reddit with and without proxies. This will help you determine how much additional traffic is being consumed by the proxies.