Starting a new site for renting items. What's a good base ecommerce to start with? Solidus? Do any of them handle rental items natively?
Plan to host in he heroku.
Having worked as a core contributor of Spree, I think it can definitely serve as a good base. You get a very good base of inventory management, basic UI, promotions, payments and more. For rentals you'll need to add some custom logic like start and end dates of rental and calculation of price on the basis of that. This will require some custom logic but you could define the rental for each day and accordingly increase the quantity on backend logic for number of days. If you have a pricing that decreases with number of rental days, then there is an extension - spree_volume_pricing which you can use to decrease pricing as number of days increase. Other logic depends on the features you are planning but Spree/Solidus are the best frameworks designed for this, at least in Rails.