Is there no limit to power levels? Since Jiren and Frieza don't have godly ki, we are able to understand that you can attain the power of a god through regular training; that regular ki can go as high as divine ki.

Based on existing knowledge, how much roughly is Jiren's full power level? (the power he plans to use on Beyond Super Saiyan Blue Vegeta and 20+ Kaio-Ken Super Saiyan Blue Goku). 

My guess is based on Super Gogeta's power level of 2,500,000,000 that Jiren's full power level is 189,000,000,000,000,000.
We have no idea which are the multipliers for super saiyan god and super saiyan blue, and we have no idea which is the current base power level of Goku and Vegeta, so it's impossible to give power levels with figures (numbers). 

If we try to determine with a number the base power level of Goku and Vegeta (which seems to be about the same for both of them for the fights and sparrings they had in Dragon Ball Super) we find a lot of incongruences or very hard to fit situations. Also with the other transformations


Fake Vegeta in base form (which is as strong as Vegeta) was able to defeat SSJ3 Gotenks. 
Goku in base form was able to overpower Freezer 4th form, Freezer 3rd form was able to almost kill super saiyajin Gohan. 
In one movie Beerus says Goku in base form isnt as strong as Freezer (4th form) 


So according to some data, Goku or Vegeta base form could be weaker than a super saiyajin, and according to other data it could be stronger than a SSJ3. Situations like those can only be fixed with speculation, no with the dialogue or things said by the authors because they just didnt try to fix those inconsistencies. So, being us unable to give number estimations since they could vary very widely, I believe this is the only thing we can say. 

Super Saiyan Blue Kaiokenx20 of Goku, plus Ultra Super Saiyan Blue Vegita which seems to be in a similar level than Goku Super Saiyan Blue Kaiokenx20 , gave some fight but no damage to Jiren. This tells us that Goku (who is using the power of 20 super saiyan blue) plus Vegeta who is using a similar power (who together has a power around x40 super saiyan blue) are weaker than Jiren. Then Jiren power level has to be somewhere between x50 to x100 super saiyan blue.