A few thoughts come to mind:
The first link is 1,000 SFX for 22 pounds (basically $30 USD). That's really cheap when you think about the number of sound effect files. Of course, not all of the sounds included will apply or fit your game. The second link has 155 SFX for $20. That's a bit more cost per sound effect file but still QUITE affordable.
If you cannot afford to pay $20-30 for your game... then you need to re-evaluate some things in your budget and your goals.
What kind of sound effects do you need exactly? There are some sounds that do an a la carte method and I've used some of those for source sounds myself:
www.soundrangers.com
www.sounddogs.com
Give those a shot. The other thing is you'll get the best results by hiring a sound design or an audio professional that can go through and make all of the sounds have the same balance and feel. This is especially true since you'll be grabbing source files from all over the place. Odds are your final sound mix will be all over the place and not feel cohesive because of this - so a sound professional can really help in this case. If you truly cannot afford to spend any cash for such work, consider making an exchange of services. You'll code their website for their audio work. You'll create their new logo and banner graphics for their audio work. Etc.
Is your game finished? The other thing you could consider doing is working with really cheap, potentially lower quality audio work for now if your game is still in development. Get everything else done and then see if you can get an audio pro to replace the audio work for you once the rest of the game is locked in place. But if your game is still really rough... then maybe make due with what you can get.
Best of luck!