cheap + effective vit c serum & alpha arbutin

hey yall. i just started my skincare journey to have a more balanced skin tone and since a ton of folks recommend BOJ's deep glow serum because it contains alpha arbutin, i am wondering if i can replace it with something like revox alpha arbutin? or other local european products? i'm kinda torn between buying what is expensive but 100% works (BOJ) and between starting slow with cheaper products. I also kinda need to fix my uneven skin tone in a ~ 1 month (friend's wedding deadline!)

(ps: on the vit c serum side of things, i got a local (italy) brand called "Dropology". the serum is much cheaper than many other ones which is making me suspicious but it's a start to build my skin barrier to tolerate.)