Lot of peoples try to find router with 4G SIM Card slot and RJ45 Ethernet Port. Wireless internet user is a different segment than wired internet users. Depending on country, some of the providers sell such devices, sometime discontinue too. Quite unfortunately, number of such routers is not huge in number and price not exactly lesser. 5G likely to become norm around the year 2022-23. So for the most, the devices going to be usable for 4 years from today. It is not practical to spend more than $100 for this work. Biggest matter to clearly know whether the router has SIM card or not.
Router With 4G SIM Card Slot
Huawei is major manufacturers of these kind of routers. In India, AirTel used to sell Huawei B310 router, which is still a good option at affordable rate.
Huawei’s other models are Huawei B315, Huawei B525, Huawei B593, Huawei B612, Huawei B715 and Huawei E5186. All of these models have SIM card slot as far my knowledge goes, yet it is practical to check on Huawei’s site for specification (and probably photo) :
Huawei identifies the product line as “LTE Router”. Basically, Huawei mainly manufactures them to sell via the service providers. Option of models is limited and usually known via country specific providers. If someone wants to avoid Huawei, then another brand is TP-link. There is TP-link Archer MR200. There are other some brands as well.
However, Huawei B310 is cheapest router. Why these LTE routers are so costly and relatively rare to find? Because these routers have part of SoC same like any modern smartphone plus have the router function. Commonly, offices purchase routers for wired internet. There are Wi-Fi to ethernet adapters (which do not cost huge). If using a spare smartphone as Wi-Fi hotspot does the job then probably buying them will solve your need. However, ethernet network performance of the LTE routers usually better.