Can multiple Promotions be applied to a transaction in Tagrain?

Can multiple Promotions be applied to a transaction in Tagrain?

No, at any point, only one promotion can be applied on a product. This is because when a product is scanned on the transaction grid, the application is smart enough to know if it is covered in more than one promotion(s) defined. If it is covered  in multiple promotion(s), it checks the order in which the promotions should be applied. In cases where the order is NOT specified, the promotion that was created earlier (based on date / time) takes precedence.
To be able to set up and configure in-store offers and promotions you must activate the Offers, Discount, and Pricing Management plugin. Promotions configured in the application are set to apply automatically when a certain condition is met.
Plugins in Tagrain are either Subscription Based or License Based. So the price that you pay for your plugins is based on the number of POS terminals that you have in your setup and the number of licences that you have acquired.
There will be no change in your subscription amount in the current billing cycle if you are only deactivating the Offers, Discount, and Pricing Management plugin AND not updating your Store / POS count.