My 8 year old is having meltdowns over video games

Help, my 8 year old just recently started having meltdowns and throwing mini tantrums because I won’t buy him V bucks for his Fortnite game. I explained to him that I am on maternity leave and aren’t making much $$ so I need to save for our bills and the important things. But he just doesn’t get it. His tantrums, nagging, and pouting when he doesn’t get his way is getting really bad. He never used to be this bad and I’m not sure what to do about it. He’s 8 and will be 9 in December. I really thought kids outgrew this type of behaviour by now 😰