You will also find them on my Lists pages. This is the ultimate goal. However, there is no shortcut to getting there. If you have only 25 subscribers, no one is going to pay you to advertise in your newsletter. On the other hand, just because a newsletter has 20,000 subscribers, that does not mean they are the best.
Some small newsletters have a much better targeted market.
Once you build your newsletter to over 500 you will be in a position to charge for advertising. Ad Swaps are your best bet until you have built your subscriber list. Most everyone will swap ads with you. Also most will remember those days of getting started. I have only had one newsletter turn me down and they had over 30,000 subscribers.