documentclass[12pt,english]{article}
usepackage{siunitx}
sisetup{group-minimum-digits={3},input-ignore={,$},input-decimal-markers=
{.},group-separator={,}}
begin{document}
begin{table}
begin{tabular}{lS}
Row1 & $226,108 \
Row2 & $8,498,296 \
end{tabular}
end{table}
end{document}

documentclass[12pt,english]{article}
usepackage{siunitx}
sisetup{table-format=7,
         table-space-text-pre = USD,
         table-align-text-pre = false,
         group-separator={,},
         input-decimal-markers={.}
         }
usepackage{etoolbox}

begin{document}
begin{table}
newrobustcmdUSD{$}
begin{tabular}{lS}
Row1 & USD 226 108 \
Row2 & USD 8 498 296 \
end{tabular}
end{table}
end{document}