Just be careful with the oscommerce template route, here's an oscommerce template checklist:
1. Is the template a fully working oscommerce installation or just a graphic picture of what the design should look like. If it's the latter then you will have your work cut out customising oscommerce to look like the design and it may not even be feasible (people can easily draw things that aren't feasible). At least templatemonster lets you see the template in action in a live demo, this is a lot better than some template providers.
2. Even if its a fully working oscommerce installation you will still have to install this on a website, and it is not straightforward, especially for those with little experience of PHP/MySQL/Apache/FTP etc.
3. Is the template a UK business one. If not you will have further customising work to do, most templatemonster templates, like oscommerce itself, have a US slant/feel (e.g. 'cart' rather than 'basket').
4. Is the template a professional one, rather than one that just looks good in a screenshot. If not you will have further customising work to do, e.g. adding security to ensure than the admin area is password protected, adding other contributions required for a professional site
5. Does the template include other oscommerce modules (e.g. auto thumbnail), if not then it will still require further techie customisation to add these features. With most templatemonster templates you cannot tell whether autothumbnailing is present, in most cases it isn't, and they hide this in the live demo by just having nice small thumbnails that enlarge onto nice small thumbnails again (not larger images)
6. Does the template include stock photos you intend to use, if so make sure it is from a reputable source and the template designer has the license to redistribute these images, otherwise you could end up getting sued by the image owner, e.g. gettyimages. (This is something to be aware of when buying any cheap template). Templatemonster was actually sued by Microsoft (Corbis) for this a few months ago.
7. Does the template include support. With an oscommerce template you are buying a system based on default oscommerce code that has subsequently been changed. If the template supplier doesn't support this code, then who does? It will be difficult to get help from the oscommerce forums since not only do you not have a standard oscommerce setup, you also dont know exactly what is different about your code from the standard code.
8. Be aware that oscommerce templates are a bit of a misnomer, they are not like a skin for your media player, or a theme, or wallpaper, they are complicated changes to already complicated oscommerce code. In most cases an oscommerce template is a customised oscommerce system, not a plug and play design theme added on (default osCommerce does not have this capability).
9. Are there any other oscommerce modules you need to add on (e.g. PayPal IPN). If so this will be even more difficult since the installation instructions are based on installing to a default oscommerce setup not a custom 'template' one.
10.Check that the template has customers using it, and contact those customers to see what they think of the template, how easy it was to setup, what was the true cost including support further customisation by the tempate owner etc.
11. As with most templates, never assume that because a picture of a system looks cool, or even a demo looks cool, it will actually work in the real world or is a working system.
12. Be aware that with the default osCommerce setup, even what appears to be the simplest of confuration changes, e.g. switch off the currencies box since I'm only selling in the UK, usually requires a PHP code change!
13. Some webhosting packages include osCommerce already installed, this doesn't necessarily mean that the web host will support your osCommerce setup, and they definitely wont support it if you overwrite it with a template setup.
14. Is there a money back guarantee if you find the template unusable or it is just 'sold as seen'
For a small initial outlay for a 'look' you could end up spending a lot more using the services of PHP/osCommerce professionals trying to get the system you actually want.
Personally I do not recommend templates, unless you know what you are doing with osCommerce, PHP, MySQL, etc.