@Jenny_Simons you may find some utility in upgrading your own account to Trello Gold, which allows you to add up to 3 powerups to any board even if the other users on the board are free users and the board is part of a free team:
That might be a stepping stone for you to then make the case for those clients that they should upgrade to Business Class.
Also shameless plug for my own product here but if you're a VA typically you'll need to manage email for your clients, I created this thing that allows them to put their email in Trello where you're able to collaborate on it with them and reply to emails from Trello:
Hello Community! My name is Brittany Joiner and I am a Trello enthusiast and Atlassian Community Leader. I'll be sharing with you a series of videos with my top tips on how to best use Trello...
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