The themes support Buddypress or Job manager will be cost about $63 on themeforest and themeforest will mark those themes as supported. (Example Avada theme). That is great way to save your money.
Almost themes are saling do not support to display nice with these plugins.
But if you want to use BBpress with our theme you can follow intruction to enable sidebar.
1. Firstly, create new file buddypress.php on our theme folder (ex: wp-content/themes/linstar/)
2. Copy content of single.php file to buddypress.php
3. Then go to edit page on admin panel and select sidebar you want to display for that page.