I believe in the power of a good prototype. Many designers will use arts and crafts supplies to makeshift a hideous but playable game, which is fine in the early stages. But when I'm going to have my game playtested, even if it's just with friends and family, I want to have a presentation that makes an impression. I want people to take this game seriously. I want them to know I am a professional. I don't want them to simply entertain my idea and not really care. The more serious I am about the endeavor, the more serious they will be while critiquing. Having solid prototypes shows you have invested time and money and will be going the distance. You are more likely to get help if people think their effort will actually result in a real product.

While making fairly full-blown prototypes in the early development stages doesn't make a lot of financial sense, I still do it. I don't recommend it. But I do it. A few decent components and some thematic artwork can really help playtesters get into the game. Some basic colors, icons, and clipart will help make the game more digestible. Your initial game will have enough problems, so making certain elements more intuitive will help the playtesters overcome the ticky-tacky issues and focus on the heart of the game, the system itself.

Plunder First Prototype

That's my very first playtest of Plunder. Just me, my brother, and my unenthused dog. Admittedly I went too far, probably didn't need to design a box and a rulebook. It was my first ever game and I was excited. But guess what: my family saw that excitement and took me seriously. I had their full support. I played that prototype once, threw out half the components, and restocked. And I kept repeating that process. I took that game box everywhere. I could get anyone to play. If the game came in a shoebox, there's no way I receive the same amount of interest and enthusiasm. They knew that product would be available for sale one day and they wanted to be a part of that. You want people begging to playtest, you don't want to have to beg them.

​Here is a list of websites that make board game prototypes and sell game parts: 

The Game Crafter
Probably the main place to get prototypes made. They also have a bunch of game pieces for sale. Their website is not super intuitive though. 

Board Games Maker
Another place to have prototypes made. They're more expensive than The Game Crafter but their interface is much more intuitive.

Rolco Games
They sell game pieces.

Spiel Material
They sell game pieces.

Wood Crafter
They can laser cut custom wood shapes.

A 3D printing service for plastic pieces.

A 3D printing service for plastic pieces.