I thought I should warn about few things before you go online with a ready-made WordPress theme. I know few people who already curse them…
These themes are using far more image sizes than necessary, and they ignore the default 3 system images sizes (Thumbnail, Medium and Large). One of my client has a site which generates six extra size version next to the default three which gives you extra 9 jpg files, with a combine size of 150-200% of the original file. For example for every 250kb picture you end up having 9 size version with a size around 300-400kb.
Of course the system generate these files for a reason, but most of the clients does not use more than 30-40% of the available functionalities and/or layouts what the system have to offer. For every 100MB web space you lose 60-80MB web space with no reason.
My advice: If you have to buy a theme, take your time to choose the right one. Have a look at all sub-page layout and all the function and choose a theme closest to your needs. If you need a simple website, with 3-6 sub-pages do not choose an overcomplicated theme with zillion custom post type: you are never going to use them.
A simpler, more compact theme can be easier developed further in the future.
No matter how many articles you can find on the internet about NOT integrate a plug-in or a functionality into the theme folder, unfortunately developers keep doing this. The most commonly committed mistake is to bundle the theme with a customized drag-and-drop page builder. Its look very cool in the description of a theme that you can build a website easily with it, the only problem with it is that this is not a purpose of a theme. This is a functionality of a plug-in you should choose independently from you theme files. One of my other client cannot have a system update because the customized, built-in page builder of his theme is not updated to be compatible with the latest WordPress (while the original page builder is).
My advice: Consult your developer / web designer at first to find out if you need a page builder at all, or which one is the best for you as a stand-alone plug-in. Write a list with all the functionality you need now and probably going to need in the next 2-4 years, and look for the best, most commonly updated plug-ins available.
You also have to look out for shortcodes (definitely if you have no idea what a shortcode is); and you also have to be very careful with choosing plug-ins if you need a multi-language website.
Why you should avoid these theme?
You website gets deprived of the opportunity of the freedom of future developments. They turn your self-hosted website into a one-in-a-million, “blogger.com” styled web site with restricted functionality. Just like you would register for a free wordpress.com website…. As for you is not possible to know all the possibilities you can have, you might end up choosing one or two “really cool” feature and loosing dozen of other you don’t even know about, but could serve you better.
This is a good solution for the first few months for your business, but believe me, there will be a point when 99% you will regret your fancy 49 dollar theme.
Find a developer you can talk about your plans. You do not have to necessarily spend money on a custom build theme, but he/she can give you some good advice to choose the right one.