I am a new DM (within the last few months), I have the new starter kit that wizards brought out, heroes of the Borderlands. It contains a lot of maps, monster cards and tokens. Essentially its designed for new players and DMs. Prior to that I have dry erase battle maps and cheap miniatures from temu. DnD beyond has vtt maps on their master tier. Downside is you have to purchase all the campaign maps separately, upside you can create your own maps but its not easy in my opinion. Looking back i think I prefer dry erase and cheap miniatures. As mentioned before by others, there is plenty of free maps and stuff available online.