Looking for cheap single switch or wall plug

@Bastian_H

What excatly do you need? A Smart Wi-Fi Plug (=HS100) or a Single Switch (Fibaro FGBHS-213)?

Alternatives to HS100 are:

Silvercrest Wifi Socket SWS-A1 (Link1) (Link2)
EasyHome Wifi Socket DIS-124 (Link1) (Link2)
Orvibo S20 (Link1) (Link2)

or G-Homa EMW302WF and EMW302WFO, OH2 integration, see here.
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A really cheap ON/OFF switch also could be an “Amazon Dash Button” (Link)