I did awhile ago and found that many of them charged on the publisher side (and a hefty % at that) so I was instantly turned off.
I have enjoyed working with sponsors who read the newsletter themselves too. It hasn't been too much work (only publishing twice per week).
My main concern when raising prices is always if that will create a gap in sponsors. I'd rather have every slot booked at a lower price than have gaps at a higher price. This is less about the actual money hitting my bank account and more about how potential sponsors would view this. If they see gaps they may conclude that the price isn't worth it...
I can vouch for not being reliant on ad marketplaces and instead having personal contact with your advertisers.
One way to increase your fees is to keep pricing the same for existing advertisers for a while and charge a higher rate to new advertisers. As you fill in spots with higher priced ads you can then transition older customers to the new rates.
I have enjoyed working with sponsors who read the newsletter themselves too. It hasn't been too much work (only publishing twice per week).
My main concern when raising prices is always if that will create a gap in sponsors. I'd rather have every slot booked at a lower price than have gaps at a higher price. This is less about the actual money hitting my bank account and more about how potential sponsors would view this. If they see gaps they may conclude that the price isn't worth it...