We buy the parts for our boards online from digikey.ca. Digi-Key lets you copy and paste other people’s carts which is great for a team like us, where one person tends to buy parts for several people at once.
When you go to your cart (top right corner), you have several options along the top (Figure 1). The main one we’re interested in is “Share a Copy.”
Figure 1. How to share a DigiKey cart.
If you’re buying something super cheap, a lot of the time, buying 1 will cost almost as much as buying 10. For example, in Figure 2, you can see to the right that 1 resistor is 15 cents and 10 resistors is 23 cents. Obviously, if you need three resistors (15*3=45 cents), add 10 to cart instead (23<45). DigiKey will usually warn you if you try to buy 3 resistors in cases like this.
Additionally, tiny parts like this are super easy to lose or break while you’re soldering, so it’s a good great idea to buy extras if it’s not too expensive. Basically, if you need one 0603 capacitor/resistor, add 10 to cart. If you need an IC, unless it’s like $45, buy an extra.
Figure 2. Example of a cheap, easy to lose, 0603 part.
When you add something to your cart, you have the option of adding a “Customer Reference” to it (Figure 3). Every part comes individually packaged in its own plastic bag. DigiKey will print whatever you write in the Customer Reference field for you on the front of the bag, along with some other nominal information.
This is really useful when one person is ordering parts for several people’s projects (hint: that’s what we do). It’s also useful if the couple lines above the customer reference field don’t do a good job of describing what the part is. For example, for the part in Figure 3, I might make the customer reference “5V buck Kiran” because I’m buying it for Kiran’s board, and he’s using this IC to get a 5V regulated output. Basically, if you’re making a cart to send to someone else, put at least your name in the customer reference field of every item.
Figure 3. Random part in my DigiKey cart with blank customer reference.