All neocaridina heteropoda
and neocaridina palmata are easy to keep, also malawa shrimp
. You have more options than just RCS.
Red rili x. RCS = rcs, rili of various grades; red rilis are derived from RCS
Red rili x. Yellow, Orange, Brown, Black = wild form brown / brown rili patterns of various kinds
Epicfish sells plain RCS for about $1/shrimp shipped (20 for $22.50), my LFS sells RCS for $4-6, most sellers have DOA guarantee. Most hobbyists know how to ship shrimp, it's not hard. quarantine shrimp for 3 days + foam-lined box + clean water + breather bag + moss + cushion does 99.9% fine with just Priority mail.
I say go for fire reds, or at least Sakura, maybe $2/piece shipped.