Body forms can be very useful for sewing and patternmaking. The challenge is getting one that resembles your figure that is affordable. There are a number of options:
Basic Cheap Dress Form
Basic cheap dress form purchased from a fabric/sewing store (such as Spotlight in Australia). You can also buy them online. Some of these are expandable, some not. Even the expandable ones are (in my opinion) not that good unless you have The Standard Figure. The shortcomings are not just limited to the fit, they are the quality of the product; lightweight and not sturdy, difficult to pin in places where the expanding produces gaps.
Good Quality Dressform
A good quality dress form, obviously more expensive. Very difficult to get in Australia, and the ones that are available are extremely expensive. One of the really good brands in the USA is the Wolf Form. If you're Australian and you want a good form, it's probably better to buy it directly from the US. Even with shipping, it will probably be cheaper than purchasing it in Australia.
Custom Made Dress Form
A custom made dress form, made to your measurements. This is easier and cheaper if you live in the USA. Two companies that make custom forms are; Superior Models www.superiormodel.com - and Wolf Dress Forms www.pgmdressform.com. From the perspective of an Australian, these custom forms aren't that expensive, but getting it shipped is another expense and a difficulty. I inquired twice about the cost of shipping, and whether they could in fact ship it, and did not receive a response! (Actually, I received an email from Superior Model saying someone would get back to me, but they never did).
Custom Made Replica of Your Body
A custom made replica of your body, such as my body cast, which was made in fibreglass. Although it good in some ways - ie. good to have an exact replica of my body to understand the fitting issues, not so good for pinning, and I have difficulty getting some things on and off.
Sew Sister makes custom body forms from 3D Printing from a dense polystyrene.
Duct Tape Form
Making a Duct Tape Form. If you do a search on the internet for body forms, you will find lots of videos about making your own dress form with Duct Tape. This is the cheapest option available, and I tried this out. Many people on the web swear by it and say they find it useful and better than shop purchased forms. I didn't have a very good outcome. I couldn't get the final form stiff enough to make it useful. Below are some images that were taken while making it, but I forgot to take a photo of the final 'form' before I threw it out. (I found it quite useless).
EXAMPLE: Custom Body Form - Fibreglass
I had a fibreglass form made by https://bodycastingsydney.com.au/
As mentioned above, I found it very useful to understand my body. I have no regrets for the getting it made, even though it was quite expensive. However, I would also like to have a custom-made mannequin that is easier to use in terms of making patterns. I find getting some items of clothing on and off very difficulty, as well as pinning. EX
EXAMPLE: Custom Body Form - Polystyrene by Sew Sister
You can have a Body Form made from a 3D scan by Sew Sister.
Here in Australia, you can have this done by Hollie in Canberra, her website is: https://www.toolsbyhollie.com/custom-dummy
If you don't live in the ACT, Hollie can still make your body form; check out her website for the details of having your measurements taken in any mPort machine. She is an mPort partner, and she can get your details of the body scan and print your 3D custom form. The cost is around $700, but I don't know if that includes postage.
Example: Making a Duct Form
Here are three images of making the Duct Tape Body Cast. It was kind of fun and interesting, but in the end, I didn't find it useful. I found it very difficult to fill it so it was solid enough to use.
I had to wear a skivvy or something underneath that could be cut up. It got more and more difficulty to breathe as the duct tape went on. It got tighter and tighter...... It's very hard to put the tape on loosely!
Once I had enough duct tape, I cut down the back, through both the tape and the skivvy, and took it off like a garment.
Once off, it kept its form to some extent; it sat on the table upright for a while, before sinking down on one side.
The website giving directions said to fill it with various fillings (including the foam that expands). I tried various things but never managed to get it sturdy enough to be of any use.