Free plugin to create "Turbo Tax" like forms

Hi,

So I have a website and I would like to add several pages/ forms in the coming days to it.

These forms will include things like:

1. Retirement calculator – where you can enter your current age, current savings, desired retirement age, future savings per month; and using my ‘investment return percentage’ and calculations, it will tell you whether you are on track for retirement or not.

2. This form will let you compare two ‘car buying’ offers. So the user has two offers from two dealers for the same car – with different down payments and different per month payments. The user will enter everything, and then “depending on my formula”, the page will tell him which offer is better.

If I can achieve this via a free plugin that will be awesome.

Any help will be truly appreciated. As you can see from my website (www.onemoredime.com), I am an expert at Finance… but learning technology.

Thank you