SPARCO makes the best neck collar. Actually made of 7 progessive-firmness component layers that absorb energy at predictable rates. About $79 retail.
Many neck collars from Simpson, OMP, TeamTech, etc etc. are under $50. {I'd sell you a TT for $43)
The HANS (trademark)device requires your helmet be sent in, about a 6-8 week lead time, and $900 - $1300 dollars for an upright seat like Viper..up to $2500 for F1.
A new company is currently under SFI testing on an upgraded neck and head restraint (NHRD) Testing involves sled-test crash simulation. Will not be avialble for 90-days or so. Price point BELOW HANS. Stay tuned.