My friend finally told me that he wanted to keep his 5" achromat, frankly, it's expected. For this price, he better off keeps it himself. Of course, I would let him keep it and I just told him, if one day he wanted to sell it again, he should contact me first.
After that, my mind swing to something else nearly immediately. Another friend is selling a Borg 101ED, and it's of course a far better scope. It's smaller in aperture, but its far higher in quality. It will be useful for deep sky work, solar and lunar, as well as planets at high power. And more importantly, it's also lighter and usable on my TG-SP II! It won't be great, but it will work at least unlike that 5" achromat. However, it's more than 15 times in terms of price.
I would hold myself, since I have been spending too much these days for the solar eclipse trip, it's no good to keep doing so. Desire is always unlimited, so to exercise self control is the only way out.