First you should define "cheap". How much are we talking about ? What's your budget ?
Python is good for trading, even better when your trade route use an outpost.
And you can make a build that will allow you to do trading + missions when you're bored. True multipurpose ship.
But for BH I don't think it's the best choice, especially with a cheap build. There are better choices than the Python (Viper, Vulture, FAS...) but again, what is your budget ?
I've got a Python for trading and it served me well, since I could buy FdL and FAS.
200 millions credits grind, damn that was long... but with short sessions and good music it makes it "easier" to deal with the grind

Need to do some more money to make a more multipurpose build now, but avoid a cheap build else you could be disappointed I think.
I used this for my trade build :
http://coriolis.io/outfit/python/06D6D5A4D6D6D5C-----040404-050505044a03020201.Iw18eQ==.Aw18eQ==
It costs 69 millions, but if you can buy everything in Li-Yong Rui systems it will get down to 59.
Then I will go for something more multipurpose :
http://coriolis.io/outfit/python/07...3580201.Iw18SAMJA===.CwBj5BGboJn6UTGAZlSIA===
You need 33 millions to upgrade from the previous build, 28 in you buy everything in Li-Yong Rui systems.
You have an armed trader that will allow you to do something else than just trading, for when you want to kill the NPC who just interdicted you or do some missions. But it's mainly a trader.
What's important is A thruster and A distributor, you will need them for combat. 7C PP because it's more than enough and it's cheap, the 7A is worth a stock Python =]
SCB are an insurance if something goes bad and you need to flee. Python MLF is high (4th) so you can low/high wake easily almost anytime, just pop a SCB if needed during your escape.
And pop some chaff if the enemy use gimballed weapons. Works in PvE, for PvP I think it's useless if your opponent is not stupid (just need to deselect target to get fixed weapons and select again after).
When you have more than enough money, you can get 6A shield, bulkhead, 7A PP, more SCB if you play with it (SCB stacking is stupid, only one module like shield/scoop... would have been better but well ^^). But then you're building a little cruiser worth 190-230 millions credits. Not something you would call "cheap"
And don't forget the insurance cost in the equation, make sure you have enough credits after upgrading your ship
If you want to stick to the Python for BH, you can start with something like this maybe :
http://coriolis.io/outfit/python/07...40403020201.Iw18eQ==.CwBj5BGboJn6BmSjHFSIA===
Enough SCB to keep it safe while you test the build and see if it's good for you. And change the weapons to suit your gameplay.
About SCB they have been changed with 1.5/2.0, so not sure about the heat generated by a class 6 to be honest. You might need to get a lower class.
Best thing would be to buy one, get out of firing zone of station/outpost, launch a SCB to see how much heat is generated and get a lower class one if it seems too much.
Better test it before firing one in combat and get 200% heat and everything turns bad then xD
Last thing, when searching for modules you can use :
https://eddb.io/station
Just set the power to Li-Yong Rui, select ships and/or modules you need, and you will have a list of stations that could have them.
15% discount is always welcome
P.S. : sorry for typo and others, english isn't my native language.