I run a small fitness training business and wish to purchase an existing training studio (including its entire rolodex of clients and equipment).
Buying an existing business can be a great way to accelerate your transition from employee to business owner - as theoretically you'll have revenue and be able to make a more seamless leap into full entrepreneurship.
Doing so without collateral creates some limitations, as it will likely mean taking debt financing off the table, with the exception of some peer-to-peer options. While those can be viable - the perception of increased risk that comes without collateral means that the interest rates will reflect that - and might be prohibitively expensive. If you do decide to take the leap with a higher interest peer-to-peer loan, closely examine things like pre-payment penalties or restrictions.
Crowdfunding can be an option - but unless you've got a strong support network that you think will back your play - its an uphill battle. Crowdfunding investors tend to look for scalable high growth opportunities - rather than cashflowing IRR type investments (like yours represents).
Often, the best option in these cases is to look for full or partial owner financing. They know the business - they know what it will support - and they'll be good at assessing your ability to be successful with it. Said differently - if they aren't willing to support your purchase of the business financially - it might be a signal that all is not well behind the scenes.
I'd be happy to discuss the decision of buy vs. build - it is one I've stared down countless times in my career as an entrepreneur - and I've taken both roads.