Well to be honest, it's usually one of the below depending how often you need to email your DJ promo list and whether or not you are doing your own distribution.
Fatdrop accounts costs £50 with a monthly fee starting at £35/month.
Label Worx charge £7.50 / promo campaign.
Pricing for the promotional system starts from $23.99 / month.
Pricing starts at £40/month.