I have a YPT-400 that I bought used for quite cheap; it's the "export model" version of the PSR-E403, which was the model prior to the PSR-E413.
I also have a PSR-E433 and a PSR-E443 that I bought new; they're more recent models than the PSR-E413.
Keep in mind that the PSR-E models are low-end Yamaha keyboards, so they don't sound as good as the PSR-S models, and don't have as many voices and feature functions. The PSR-E and PSR-S models do use the same type of tone generation technology (AWM2), but the PSR-E models use a simpler version of Yamaha's XG MIDI standard called XGlite, they have a lower maximum polyphony than the PSR-S models do, and their voices can't use as many elements as the PSR-S models can.
I'm not saying that the PSR-E models don't sound good, because I think many of their voices do sound very good-- although some of them don't sound very convincing to me (e.g., the violins), which I think is pretty typical of ROMpler keyboards in general (some voices sound great, other voices don't sound so great). I happen to like my PSR-E4xx/YPT-4xx models very much, although I do have a lot of virtual instruments that I can use to complement them.
The PSR-E4xxs/YPT-4xxs are the top-of-the-line models among Yamaha's low-end keyboards, and the main reason I chose the PSR-E433 was because it has menu functions and two assignable knobs that can be used to modify their voice parameters-- the EG attack/release times, and the LPF cutoff/resonance settings. It also has arpeggios. The PSR-E413 has those features, too. But you shouldn't pay a lot for it-- I'd say somewhere between $100 and $200 used, depending on its condition and whether the person is including any extras with it (keyboard stand, keyboard bench, etc.). I paid $80 for a used YPT-400, and it was in great condition, so $100 would be a great deal on a PSR-E413, but I wouldn't pay more than $150, and that's only if it includes the power adapter.