Imperial Paperwork...

[Srynerson]

If you wanted to star up a trading company, would you have to go through the Imperial equivalent of the Teamsters?

In ESB, Lando tells Han and Leia that Cloud City is "small enough" that it doesn't fall under "Imperial jurisdiction". Leia then says "you're part of the mining guild then," to which Lando replies that Cloud City isn't because it is "small enough not to be noticed".

I always thought Cloud City was an illegal operation. Lando left out all registration in order to sell to anyone he wants at a price he likes and without paying taxes.

I don't doubt that Cloud City was an illegal operation, but Lando's comment about the lack of "Imperial jurisdiction" followed by Leia's question about membership in the "mining guild", suggests that the guild would have some sort of regulatory power over a facility that would not otherwise be regulated by the Empire. If saying the facility was not under Imperial jurisdiction was synonymous with saying it was illegal, Leia would presumably not have needed to ask the question about guild membership.

[Instant Sunrise]

To me, it sounds like price controls exist in the Empire in some form. It could just be on goods & services that are vital to the operation of the Empire, like tibanna gas in the case of Bespin. However, as for the effectiveness of said price controls, there is the appearance of a black market for tibanna gas, so it seems that their price controls are not as effective as the Empire would like them to be.

[MKSheppard]

They exist; here's an excerpt from HAN SOLO AT STARS END:

“We got your description from the docking bays supervisor,” the Security Police sergeant answered. “Your ship’s been impounded.” He threw the IDs back on the table. “Failure to conform to Authority safety standards.”

Han’s mental processes switched tracks. “She’s got all her approvals,” he objected, thinking he ought to know, having forged them himself.

The Espo waved that away. “Those’re outdated. Your ship fails to meet new standards. The Authority redefined ships’ performance profiles, and from what I heard, buddy, your freighter violates hers about ten different ways and doesn’t appear on the Waivers List. Just on external inspection, they found her lift/mass ratio and armaments rating way out of line for non-military craft. It looks like a lot of radiation shielding got removed when the thruster ducting was chopped and rechanneled. Also, she’s got all that irregular docking tackle, augmented defensive shields, heavy-duty acceleration compensators, and a mess of long-range detection gear. That’s some firecracker you’ve got there.”

Han spread his hands modestly; this was one tune when he didn’t feel like boasting about his pride and joy.

The Espo sergeant went on. “See, when you run a hot rig like that, small payload, overmuscled, the Corporate Sector Authority starts thinking you might take a notion to do something illegal with it. She’ll have to be refitted to original specs; you’ll have to appear and make arrangements.”
Hah laughed airily. “I’m positive there’s some error.” He knew he’d been lucky they hadn’t forced the locks for an inboard search. If they’d seen the anti-sensor equipment, jamming and countermeasures ap-paratus, and broad-band monitoring outfit, this would have been an arrest party. And what if they had found the contraband compartments?

....

Han’s smile became pained and sympathetic. Platitudes of understanding rolled from him. Meanwhile, he considered his dilemma dispassionately. The Authority would want a full accounting of ship’s papers, log, master’s credentials. When those showed discrepancies, there’d be a full ID scan: pore patterns, retinal and cortical indexes-the whole routine. Eventually, they’d find out who Han and his first mate were, and then the trouble would really start.