I absolutely hate flux core. You will find the gas produces a nicer weld and the splatter is decreased greatly.
A bottle of gas will last a fair amount of time but bigger bottles aren’t much more to fill than the smaller ones. I run two 80cuft bottles so I always have a full one. Most places like airgas will let you change up/down on bottle size by just paying/refunding the difference in case you ever want to switch.
I use C02 on my Hobart 140.
You can find a 20 lb C02 bottle cheap. They are the ones used on the fountain drink machines.
I will never go back to flux core.
Im a novice and only weld a little.
I started with co2 and keep a bottle around as i find it better for welding outside. For the shop, I keep the 25% co2 /75% argon mix. On my last exchange, I gave $38 for a 80cuft cylinder.