For things like lingerie, sensual body products, simple toys...I consider $20 or so inexpensive (at my stage in life/sex toy experience). For cuffs, other bondage gear, good G-spot vibes and of course sex furniture: the sky's the limit.
So I fall somewhere between. For instance, the Liberator Wedge vs Heart Wedge; I'm sized so that the Heart Wedge works great for me. It's cheaper than the Wedge so I consider it frugal
And buying lubes in "bulk."