I have to work about 2 hours a day with laptop on the go and looking for a cheap way (no hotspots) to get into the internet with a stick - no big downloads.
Who can give you tips?
The easiest way would be if you ask your mobile service provider. Often, the additional data rates are cheaper than the second card.
Better than a USB stick is a wireless router with SIM card, because for multiple devices simultaneously usable. Example: https://www.amazon.de/...B015U1JS74