Famas might be a cheaper alternative for a time being, but I see the m4 lasting longer. I still see a lot of sparrers use the m4, so buying it now might save u some money later on.
Best budget guns (imo)
- desert eagle
-acr (12k)
-aa12 (60k)
-pdw (75k I think)
And then just save for bar. Hope this helps.