I don't disagree that a professional site design and development can be important - and its hard to argue this in detail as the OP was very vague in his requirements.
My point was if a business is just starting to sell widgets online then working out whether there is a demand for that product is way more important than spend $1000's of dollars on a top-of-the-line all singing-dancing website - that can come later if there is the demand for the product. I personally know people who have sold websites for $10,000's of (US) dollars - all based on a simple WordPress site - the buyer was buying revenue and traffic - not a pretty design.
No sane person would decide to build and open a new real-world store without knowing in advance whethere anyone will come and buy their widgets. They will start on the kitchen table and sell thru local markets to first measure the demand.
Online, spending more than a $100 or so on a website on a "bright idea" - which is what I think the OP may be talking about - is the equivalent of building that pretty shop without the proven demand.
Once the $ start rolling sure re-vamp the site - if its needed - or revamp it if you have lots of visitors and no sales - but this is after you have the most important bit sorted - leads.
No there are no guarantees about hitting #1 in Google - but a decent
SEO can tell you whether or not you have a chance and how long its going to take and how much work is going to be involved (and most of that work won't be on your own website - it will promoting your site elsewhere). There is always something you can hit #1 for - it just may not be "widgets" it might be "shiny blue Queensland widgets in size 10" - which lis a better qualified lead anyways.
Oh and in my opinion the last thing that any business should do is tie themselves up with one provider on a monthly plan which will make it hard to move their site elsewhere in terms of hosting or the technology used to devleop their site - as their business develops.
That is the #1 reason I recommend WordPress as the solution for most new businesses - its open source - and in English that means that even if you do pay someone to develop the site for you - you can host the site anywhere and if you don't like the ongoing service of either your host or your developer - you can change them both easily.