Hoping upsell is the right phrase!
I have reasonable teeth for my age (mid 40s). The top set are reasonably straight, bottom set less so. Only 1 filling. Never had a brace so they've never been straightened. They are average teeth, so nothing like a set of Towie veneered gleaming white gnashers.
I'm an NHS patient at my dentist. I go for a check up every 12 months. Each time they tell me I need a hygiene treatment which they charge £70 plus the basic bottom rate NHS fee.
This was enough (I have refused the hygiene treatment once when i couldn't afford it but they were really funny with me) but the last couple of times they're now promoting braces with leaflets handed to you, asking you if you're interested etc.
At my most recent appt, i was asked again. Said I'm not interested, joked I was too old for braces. Response was Oh lots of our patients are in their 50s...so did i want to think about it, it was ONLY £3k (!). I said I couldn't afford that. To which the response was we'll do you a payment plan 
.
I then got a hard sell about how my teeth were overcrowded and will decay because I can't clean them properly...although a brace won't make any difference unless i have teeth out which isn't included in the £3k! And my teeth aren't level, and this will be more obvious when they're straight, dentist points this out and tells me then I'd need veneers as well or they'll look wrong!
Thankfully that was the end of appt so i could leave. But i have to go back for a filling in 2 weeks and am already dreading a repeat of the whole convo!
Why have they got to sell me stuff? I don't have £3k for teeth, let alone what this would actually cost with veneers etc!