The question I hear the most often when it comes to heat transfer vinyl is "Do I NEED a heat press?" The answer depends a lot on the materials you work with, how much you do and if you sell your creations.
The burning question- do I need a heat press? To help you answer that question, I have created a flow chat:
This flow chart starts with the most basic of questions- do you use heat transfer vinyl? If you do not, then you don't need a heat press. If you work with regular adhesive backed vinyl, it comes ready to stick onto your project, no heat required. If you work with heat transfer, move on to the next question.
Do you sell your creations? If you're making items to sell, you probably want to invest in a heat press. While you can iron your items on with a regular iron, a heat press will give you a more professional finish and ensure that your heat transfer stays on your product. If you sell your items, invest (and write it off as a business expense).
If you do not sell your creations, the next thing to consider is how much heat transfer do you work with. Do you have large volumes? If you only do a thing here or there for family or yourself, you don't need a heat press. If you make a lot of stuff for family or yourself, you might want to look into a heat press. You can get by with an iron, but takes more time and effort. How valuable is your time? Consider that you may be spending over a minute per garment with your iron, so you might want to look into a heat press if you have a lot of things you're making.
Finally, do you make large designs? If you have small designs that fit under your iron, you can transfer with one press, so you might not need a heat press. If you have larger designs, and you have to move your iron several times to cover the whole design, you will probably want to consider investing in a press.
In short- if you make items to sell, make a lot of items or make items with large designs, you may want to invest in a heat press. If you only make items for yourself, with smaller decals or don't mind spending time ironing, you probably don't need a heat press.
While a heat press is certainly an investment, it will help you transfer vinyl quickly and easily and give you a polished product in the end. If you can splurge, you should!