If you are looking for affordable smart switches, the Tuya devices are very affordable alternative and the can integrate with your openHAB instance.
Control – MK-SmartHouse
Complete Guide Connect Tuya Plug To OpenHAB and Home Assistant Using Tasmota
Tuya Binding issue - Bindings - openHAB Community
Tuya Convert Guide - Flash Tuya SmartLife Devices – The Dreaming Dad
Smarthome/J Tuya Binding support for WIFI TUYA Energy Meter 63A with voltage current and leakage protection (Need HELP) - Bindings - openHAB Community
Step-by-Step guide for adding Tuya-bulbs, Wi-Fi smart LED (Smart Life app) to OH2 using tuya-mqtt.js by AgentK - Tutorials & Examples - openHAB Community
BlitzWolf SHP Bargain Smart Sockets For Alexa, Google Home, Open Hab
OpenHAB vs Home Assistant
LSC smart devices - Installation - Home Assistant Community, lsc smart connect
Using Tuya Smart Products to Empower SME Smart Home Solution Installers - DusunIoT
Adding Tuya device to OpenHAB3.
Step-by-Step guide for adding Tuya-bulbs, Wi-Fi smart LED (Smart Life app) to OH2 using tuya-mqtt.js by AgentK - Tutorials & Examples - openHAB Community
Tuya - WiFi relay 3x devices- Android/iOS app - Moes MS-104C Botland - Robotic Shop