Looking up the DNA cost on the Fandom wiki, it would cost you 11,820 in DNA to buy once you unlock it. Of course, you can get that on discount (up to 20% off for VIP but at least 15%) so really it’d be even less.
From what I’ve seen, the trades offering dinos for Loyalty Points (or DBs) are rarely good in terms of relative value. The LPs seem to have a trade value of at least twice that of DNA, but almost all the dino ones I see for them are 1:1 or close to it, so you’d essentially be paying over twice what the DNA cost would be for it. Which isn’t that surprising, the trader knows people are likely to pay a premium for a dinosaur they want.
If you really want to make sure you can get to level 20 right away when you unlock him, just make sure you have that much DNA stashed up when you are getting close. At most you’d have to wait a week if you want to use the discount.
The only reason I have thought about taking any of the LP -> dino trades is if it will unlock a badge for me. Which ironically, is one that is staring me in the face as I type this, the trader is offering me Doedicurus, the fairly new super rare cavern. I’ve not found one yet, and he would complete a badge for me. but again, the cost is 1:1 in loyalty points, and he’s not going to add much to my lineups otherwise. But it’s only 2K worth of points for me so I’m definitely tempted. If I was close to unlocking the next size of the badge beacon I probably would get it, but I just moved up so have a LONG way to go now which most the remaining ones being hybrids and tournies that will take me a long time to collect. So probably will pass on him.
That’s ironic you are having to save up to make sure you get a VIP you already have. I seem to ONLY get ones I already have all the time, it’s starting to get frustrating that I have as many as 4 of some VIPs (as well as 2 and 3 of others), but at least half of the ones in the pack I don’t have at ALL yet. I’m holding off myself though on leveling up any of them to level 11, let alone 20, I haven’t even bumped them up to level 11 as the jump in stats is quite large and so I’m waiting until I have enough to make at least 2 of each that I level up and get more of my legendaries up to level 31+ as well.