I've never used 100 percent acrylic for socks. I've heard Wool-Ease (wool/acrylic blend) is okay, but not the best. I've heard that acrylic does not absorb any moisture and that they are hot and make feet sweat.
However, if it was me and I liked the yarn and I had already finished one sock, I'd just keep going. But that's just me.
KER++ Exp SPM+ Bam+ Steel+ Syn+ Cot Wool+ Lux Stash Scale+ Fin+ Ent-- FI-- Tex+ Lace+ FlatCircDPN Swatch- FO WIP+ GaugeW Alt-