I don't understand because we've recently upgraded the messages section to make it more clear about how many message views you can have.
Basic members can view up to 5 messages in 24 hours and this is displayed at the top of the page. A small yellow 'eye' icon shows the messages you have viewed, and you can view these as many times as you like. If you've used up your 5 views then a timer shows you when you can next view a message. I hope this is much clear than the previous system.
If you just want to view unlimited messages without having to wait then the Social upgrade offers this along with unlimited use of chat and other useful features.