Can I purchase the Turbo Standard product?

Here is a link  with all the products you can click on the boxes that pertain to your situation and the site shows you exactly which software is appropriate for you. From what your saying Standard would be the right one for you.

http://turbotax.intuit.ca/personal-tax-software/online-tax-software.jsp

Will my previous tax return information carry forward if I switch to the Standard Plan from the Premium Plan I used in 2014?

Please follow the directions below and you should be able transfer information. Please note that if you had Premier and you had some forms that are not in Standard which means not all information will be completely transferred over.
Transferring 2014 Information from TurboTax online edition

If you used the online edition of TurboTax to complete last year’s tax return, complete the following steps to transfer your information:

    1. Go to TurboTax.ca and select Sign In > Start or Continue My 2015 Tax Return.
    The sign-in page appears.
    Under Welcome Back! enter the same user ID and password you used last year.
    The product selection page appears.
    Choose either Standard, Premier or Home & Business.
    Select Continue.
    A page appears: Hi! We're so glad you're back.
    For the question Do you want us to transfer last year's return for (your name[s]) into your new return? select Transfer Return.
    A page appears: Has anything changed since last year?
    Choose an answer, if one applies.
    Select Continue.
    A page appears: What do you want to transfer into this year’s return?
    Choose an answer.
    Select Continue.
    A page appears: File transfer summary.
    Select Continue.

Your tax information is transferred and ready to use. Proceed with your tax return.