Spend a decent amount on DHB (aeron) or Sportful or Castelli etc. Most brands use Cytech pads, so look for a brand and model that uses them.
Whatever anyone tells you, you do get what you pay for. Yes, you can buy very cheap shorts, but they are cheap for a reason. I would say spend £50 or more
Do not wear 2 pairs of shorts, they are not designed to be worn like that, much like they are not designed to be worn with anything else under them.
On a personal note, I have bought 2 pairs of the Howies 3/4 bibs (both sizes as the first smaller size was too small) and have to say that I am not a fan of their fit or shape esp with the pad, so I would not recommend Howies myself. I am a massive fan of Sportful though for the road