I don't pour plastics yet, but have been pouring lead for many years. I've repacked bulk plastics & got supplies from Lurecraft (http://www.lurecraft.com
). Don't know if they have a starter kit, so you might try calling or emailing them and asking. They carry all types of pouring supplies, and many molds so shouldn't be difficult to make up a kit with molds for baits you'll use a lot. Maybe you can get a good deal on what you need to get started!
I also agree with Lip, Doc Irv would be the man to talk to about pouring plastics.
There have been some posts about pouring plastics in this forum in the past, so a search should produce some information. I'm sure there's also posts on Youtube & other places on the WWW. Lurecraft has some information on their site as well.
The best tip I can give is that safety should be first & foremost. You need to be very aware of all the safety requirements for the pouring you'll be doing. With lead, it's extremely hot, and there are some possible fumes & other hazards associated with lead. I have gloves, a leather apron, a respirator & other items I use when pouring & painting lead, and I know & follow procedures for safely handling lead around my house.
I'm sure it's the same with plastics. You'll be dealing with hot plastic, possibly toxic fumes & other hazards. Don't ever take your safety, the area you'll be working in or the safety of others for granted. Tackle making can be a very safe hobby but only if you know the possible hazards, know the proper safety procedures, use the proper PPE for the materials you'll be using! Never take safety for granted.