Require at least one other product to checkout

I wondered if it was possible to somehow make an attribute require a separate additional product to checkout?

ex. Only $1 when u purchase one other item

(so the customer can't check out with only the one $1 product)

Use the Low Order Fee to encourage minimum orders - Admin> Modules> Low Order Fee

I need to do this also, basically I have a store where you can purchase a camera lens, but I need to require that they choose an adapter ring for their style camera. Also, the adapter ring is a separate product that can be purchased independently. I've only been using zen cart for about 3 days but I'm trying to move over a failed development site to zen cart. The original site is https://www.demonfisheyelense.com/dev

Thanks for any help in advance.

sorry, its actually demonfisheyelens.com/dev

you can purchase a camera lens, but I need to require that they choose an adapter ring for their style camera. Also, the adapter ring is a separate product that can be purchased independently.

I don't know of a way to require purchasing an additional product, but what you're describing is pretty easy to achieve using attributes. Set up an attribute (I think I'd use dropdown for this) and enter the names & styles of cameras that you carry adapters for. If some are more expensive than others, check the "price by attributes" option on the product edit screen and then assign a price to each different camera style you list. (If they are all the same price, just figure that into the product price.)

You would need to set up the adapter as a separate product as well, to be sold separately.