To the OP, you have asked a fairly vague question. there are so many good choices in 22 semis. All sorts of models have been produced for over 100 years. Remington, Browning, Winchester, etc each have produced millions in many variations, and they are floating around the used market. All had their pros and cons, most were pretty good.
Here are a few that I like in the used market
(X means i have not shot this model, but is has a great reputation):
* cz 511 (older with wood & steel) or 511 (newer, more plastic) X
* brno 581 (an even older version of the cz above) X
* Norinco jw-20 (light, great trigger, accurate, sometimes need tuning)
* Browning SA-22 (jw-20 is a chinese knock off of this, but it goes for well over $500 new) X
* Mossberg 151
* Remington nylon 66 (creepy triggers, but very light and accurate, esp with open sights)
* Browning buckmark X
* Thompson Center (TC) R55 X
The bargains in the group above are the norinco and the mossberg, both can be had for around $200 give or take. Both are very accurate.
There are only a few guns I would definitely avoid in your place: the cooey/savage 64, remington 597, later model mossbergs made in the 70's or after. That's just my opinion, you will find some who have had better luck with these and like them.
Before anyone can really help, you need define what this 22 semi will be used for and list what is important to you and what isn't, for example:
new or used
trigger feel and pull weight
accuracy needed
ease of cleaning
importance of light weight
tube or magazine fed
magazine capacity
scoped, peep sights or open sights
plastic stock or wood or laminate stock
stainless or blued steel action