On sales leaders: I personally know some sales leaders who mentor/advise other start-up founders. This includes getting on some client calls.

However it's tricky, in that they wouldn't do it if there was a conflict of interest of any kind, they'd be more likely to do it once they know these people a bit more. There is also the WIIFM factor.

All that to say, it is possible to get help.

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On sales reps: As others have mentioned the biggest factor here will be how long it takes to close a deal. If you have quick close cycles (typical in the small to mid-market), a higher commission component or commission only is possible.

Typically, I've seen commissions in B2B to be about 7-10% of Annual Contract Value (ACV) for the first year. Mind you this is highly generalized, based on my experience.

Most sales compensation plans aim for sales reps to earn 1x base as commissions if they meet target. So a base of $60K, would result in $120K in income if they performed.

Based on this you could try finding reps on 14-20% ACV on a commission only basis, paid out on paid invoices.

To be candid, I wouldn't try doing commission-only positions for my own ventures. That said it's worth a try if there are constraints that make it hard to pay a base.

Getting part-time help in sales is going to be hard. It will depend on how long your sales cycle is too.

Sales reps will happily work on commission only if they see a huge market for your product. Which might be difficult to show with a new product.

The commission rate is negotiable at the hiring point. If they are great at sales and know there is a big market they will want a lower base with a higher commission. You should also set a commission cap at some point as your variable costs increase your profit will drop and you could end up at a point where the sales team is making more than the company.