CPR and get refreshers if you aren't feeling confident. I've asked my local WIC office for refreshers and the nurses are happy to help
I get recertified in pediatric advanced life support (PALS), adult advanced life support (ACLS) and basic life support (CPR/BLS) every two years for my job. I use all of those skills on a weekly basis at minimum, so I'm very comfortable with them. Personally, I still bought a lifevac because there's no such thing as being too prepared. Also, does anyone else ever watch your child? It's great to have for babysitters/grandparents/etc in case of emergency. Seconds count when it comes to choking and even if someone knows what to do panic can make that very difficult.
I know I’m late to the party here but I definitely recommend knowing CPR as a first line of defense. However, the lifevac is a great backup and not just for babies. My 84 year old grandmother choked on her dinner at my house but I couldn’t do the heimlich because she had broken ribs healing from a previous fall. The lifevac saved her without me having to do any damage. It also gives me piece of mind if my son is with my parents just in case something happens and someone panics
Take the cpr classes. You should have those no matter what the case. But if a lifevac makes you feel better I would say get it but do know it does not work in every scenario and having the CPR if it doesn't is a absolute must. It is intended to be used after CPR fails.