Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Palm Springs to La Paz as you normally would.
The cheapest flight price from Palm Springs to La Paz is $275. On average you can expect to pay $287. The most popular route, (Palm Springs - La Paz Leon), can usually be booked for $1,447.
This is defined as Palm Springs Airport (PSP) and La Paz Leon Airport (LAP). Codes like La Paz Leon Airport are often used to just call airports uniquely.