Looking for the most inexpensive solution. I have seen Ecolink contacts but are there any others
There are several, but the ecolink is I believe the least expensive.
In roughly low to high cost order, although prices can vary:
Aeotec Dry Contact
GoControl fixture module
Fibaro miniature door sensor
Fibaro Relay (older model)
Remotec fixture module
Qubino Zwave Plus Dry contact Relay module ZMNHND3
Evolve isolated Dry contact module
Everspring used to make one that was priced about the same as the eco-link, but it’s been discontinued.