Click here to claim your copy now — and we’ll tell you the name of this Top US Share… free of charge! See all posts by Harvey Jones Image source: Getty Images. Investing in UK shares is a great way to build the money you need to fund a comfortable retirement. Now could be a good time to buy them, as the FTSE 100 is still trading 20% lower due to the stock market crash.If you are 40 or 50 years old and have little or no retirement savings, you need to get cracking. This is a good opportunity to pick up top UK shares at bargain prices. If we get a second market crash, that could actually work in your favour by making them cheaper.5G is here – and shares of this ‘sleeping giant’ could be a great way for you to potentially profit!According to one leading industry firm, the 5G boom could create a global industry worth US$12.3 TRILLION out of thin air…And if you click here we’ll show you something that could be key to unlocking 5G’s full potential…The world’s most successful investor, US billionaire Warren Buffett, has always urged investors to take advantage of moments like these. As he once said: “Widespread fear is your friend as an investor because it serves up bargain purchases.”I’d buy undervalued UK sharesRight now, many UK shares are trading at significantly reduced valuations. Some are very, very cheap, for example, in the travel and banking sector, which have been exposed to the full force of the pandemic. Be careful around these. The outlook remains risky.I wouldn’t take big chances right now, given that you can find solid FTSE 100 and FTSE 250 stocks trading at reduced valuations. Personally, I think the housebuilding sector is a good source of bargain UK shares. Pharmaceutical companies, such as AstraZeneca and GlaxoSmithKline, consumer goods specialists Unilever and Reckitt Benckiser Group, and spirits giant Diageo are all high on my watchlist.You could wait until economic conditions are more settled before buying, but the danger is you’ll miss those bargain prices. By delaying, you’ll also miss out on the dividend income paid by your chosen UK shares.Get rich and retire earlyBuffett is clear on the importance of taking your chances when they arise: “Opportunities come infrequently. When it rains gold, put out the bucket, not the thimble.”I’d be looking for solid UK shares that have been sold off in the market crash. Then I’d aim to hold them for a minimum of five years but, ideally, far longer. That allows you to build the income you need to fund an enjoyable retirement.As Buffett put it: “We’re buying businesses to own for 20 or 30 years. We think the 20- and 30-year outlook is not changed by the coronavirus”If you are in your 40s and 50s, I wouldn’t hang around. You need to start saving right now. The good news is that there are plenty of bargains out there. That’s why I’d go shopping for bargain-priced UK shares today, rather than wait to see if they’re cheaper tomorrow.If the market does crash again, I know what I’d do. Buy more UK shares. Then sit back and wait for markets to recover, as history shows they always do in the end. It’s what Buffett’s been doing for decades. Our 6 ‘Best Buys Now’ Shares “This Stock Could Be Like Buying Amazon in 1997” Renowned stock-picker Mark Rogers and his analyst team at The Motley Fool UK have named 6 shares that they believe UK investors should consider buying NOW.So if you’re looking for more stock ideas to try and best position your portfolio today, then it might be a good day for you. Because we’re offering a full 33% off your first year of membership to our flagship share-tipping service, backed by our ‘no quibbles’ 30-day subscription fee refund guarantee. I would like to receive emails from you about product information and offers from The Fool and its business partners. Each of these emails will provide a link to unsubscribe from future emails. More information about how The Fool collects, stores, and handles personal data is available in its Privacy Statement. Enter Your Email Address Simply click below to discover how you can take advantage of this. Harvey Jones has no position in any of the shares mentioned. The Motley Fool UK has recommended Diageo, GlaxoSmithKline, and Unilever. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors. No savings at 50? I’d follow Warren Buffett’s advice to get rich from UK shares Harvey Jones | Wednesday, 14th October, 2020 I’m sure you’ll agree that’s quite the statement from Motley Fool Co-Founder Tom Gardner.But since our US analyst team first recommended shares in this unique tech stock back in 2016, the value has soared.What’s more, we firmly believe there’s still plenty of upside in its future. In fact, even throughout the current coronavirus crisis, its performance has been beating Wall St expectations.And right now, we’re giving you a chance to discover exactly what has got our analysts all fired up about this niche industry phenomenon, in our FREE special report, A Top US Share From The Motley Fool.