Do I need a shopping cart software?
 

There is only one product for sale in this ecommerce site, it is a service collecting, through HTML forms, information from its members. The site is multilingual, the members pay a fee for the service and it is not available out of the Internet.

After spending the whole day googling on the subject, one can only get a broad idea but it appears the following things are required:
- an Internet merchant account
- a gateway processor (provided by institution providing the above)
- shopping cart software

The shopping cart softwares offered all compete for better features which are not required in this case because:
- there is only one option: to purchase the service or not
- full refund of the last payment is offered if unsatisfied at any time covered by the payment
- it is not critical for this organization to insure payment has been made before allowing write access to certain files to new members
- fraud detection is not critical either due to the granting of write access on payment and the refund policy.

It seems there are "scripts" that can do the job, PHP, Perl, etc, perhaps someone can make sugestions on how to follow that line.

It would also be a bonus if someone is able to comment on "Internet merchant accounts" since the negative points do not seem to apply in this case (credit rating of applicant, type of industry like porn or gambling etc, etc).

Thank you for your help.

You don't need a merchant account until you have a really high volume of transactions. Instead you can use a 3rd party payment processor. There are lots of popular ones like:

paypal
2co
authorize.net
moneybookers

etc.

As far as the shopping cart goes you have lots of open source programs to choose from. Which one you go with depends on how much information you want to collect. Most of these programs are designed for physical goods so they collect the usual name, address, shipping info. If you need to collect more information from customers you may have to customize the shopping cart or look for an extension/plugin that allows you to do that. Anyway you can start with opencart:

opencart.com

http://forum.opencart.com/viewtopic.php?f=20&t=29845 : selling services with opencart. note the bit about disabling shipping.

You need not worry about the software having more features than you need. It's all free so you use what you need to and ignore the rest.

BTW if you are using drupal as a CMS for the rest of the site you can try ubercart. Wordpress also has a shopping cart plugin called getshopped. The advantage of using these is that they will integrate well with the rest of your site if you are already using these CMS.