Dynamic tweets allows you to send up to 20 scheduled tweets per day for free. If you’re looking to keep it simple with only tweet scheduling and you’re just getting started, I’d play with this. One con I noticed is that the site isn’t https. I always like to see secure sites when I’m sending password information.
You can also create tweet templates to speed up the process of scheduling tweets you want to repeat send. If you aren’t repeat sending your best tweets, you might want to consider it. This is a great post on the topic. But keep in mind, without the pro version of hootsuite, you can’t bulk upload scheduled tweets from a csv or excel file.