Before I took the plunge and purchased my first Thermomix TM31 I used to spend a day making curry pastes with a friend. We would make 2 pastes and take home half each. But now we both have a Thermomix so 30 seconds and the job is done. Needless to say we had to find another activity to do to spend time together.
People are driven by different factors to make their own pastes: satisfaction of making from scratch, knowing they have made it and know the ingredients, no preservatives and additives, reduced packaging, and the convenience of being able to make it right when you need it. What will it be for you? There are some good quality pastes available at good prices, so taste and price are not always factors.
I get a kick out of making what ever I can make from scratch, reducing preservatives and waste. I feel I get a better product making my own at a really good price as I buy my basics in bulk.
Once you have had your Thermomix for a little while you may find you have a better stocked pantry and don't need to purchase any special ingredients. That's what I find, so cost of ingredients often doesn't come into it for me, and the same may happen for you too.
Read more about stock pastes here
Some of my current favourites are:
Fresh Turmeric & ginger paste (great for turmeric tea & lattes)
Making Thai Green curry paste from scratch - it's easy!